Glenn Schneider - Curriculum Vita / Resume


Steward Observatory                      Home:      7742 East Oakwood Circle
933 N. Cherry Avenue                                Tucson, Arizona 85750 USA
University of Arizona                    Telephone: 1-520-296-5296
Tucson, Arizona 85721 USA                e-mail:
Telephone: 1-520-621-5865                URL:
Fax:       1-520-621-1891                


Ph.D. in astronomy, August 1985, University of Florida.

B.S. in physics (cum laude), June 1976, New York Institute of Technology.

Employment History (Chronology)

1994-Present: Steward Observatory, University of Arizona
                       Astronomer & NICMOS Project Instrument Scientist

1985-1994: Computer Sciences Corporation, Space Telescope Science Institute
                   Operations Astronomer:
                       Staff Scientist (1992-1994)
                       Senior Member of the Technical Staff (1988-1992)
                       Member Technical Staff-A (1985-1988)

1987-1989: Catonsville Community College, Adjunct faculty.

1984-1985: Department of Astronomy, University of Florida, Research assistant.

1982-1984: Space Astronomy Laboratory, University of Florida, Research assistant.

1978-1982: Department of Astronomy, University of Florida, Teaching/Research assistant.

1977-1980: Warner Computer Systems, Inc., APL technical consultant.

1976-1977: Warner Computer Systems, Inc., APL technical analyst.

Present Position: Steward Observatory, University of Arizona

Astronomer & Instrument Scientist for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Project at UofA

Synopsis. Dr. Schneider is an Astronomer at University of Arizona’s Steward Observatory, and the Project Instrument Scientist for the Hubble Space Telescope’s (HST) Near Infra-red Camera and Multi-Object Spectrometer (NICMOS). His research and instrumental interests are centered on the formation, evolution, and characterization of exosolar planetary systems, and high contrast space-based (coronagraphic) imaging systems. His studies have focused on the direct detection of sub-stellar and planetary mass companions to young and near-by stars and the circumstellar environments from which such systems may arise and interact. In concert with his scientific investigations of circumstellar dust and debris disks and co-orbital bodies they may harbor, he has played a leading role in the development of very high contrast space-based coronagraphic and near-infrared imaging systems and techniques with HST, leading to spatially resolved scattered light images of nascent exoplanetary disks. As a key member of the NICMOS Instrument Definition (IDT) and Guaranteed Time Observing (GTO) teams, and lead for the Environments of Nearby Stars (EONS) programs, these and follow-up General Observer (GO) investigations under his direction have borne substantial fruit (see Publication List).

Environments of Nearby Stars (EONS) Programs. A significant portion of the NICMOS GTO time under Dr. Schneider's stewardship was dedicated to obtaining observations leading to a better understanding of the physical processes inherent in the formation of exosolar protoplanetary systems (i.e., post-natal circumstellar disks) and stellar systems harboring substellar components. Dating from 1995, the initial foundation of the programs under the EONS umbrella was embodied in a set of (now partially answered) questions: Is there a continuity of companion objects across the sub-stellar mass-spectrum bridging the stellar main sequence into the planetary domain? How do the formative processes of protoplanetary disks and the physical properties of their constituent grains influence the evolutionary pathways that give rise to planetary systems? In what sort of local environments will such objects form, and at what distances will they be found from their host stars? How are these systemic parameters biased by the characteristics of the primary and companion objects and those of the circumstellar regions? What implications will the discovery and characterization of such objects have for our understanding of formation mechanisms? These fundamental questions defined the goals of the EONS investigations. In seeking to shed light on these, and related questions, Dr. Schneider assumed a leading role in overseeing and organizing the implementation of these highly successful programs. In concert with the conduction of these investigations, he played a pivotal part in development the HST/NICMOS coronagraphic capability, which was essential to the their success. Through his efforts, the NICMOS coronagraph has been proven as a unique instrumental and scientific resource by enabling very high contrast detection of very faint companion objects, and diffuse circumstellar extended features in scattered light imaging, in the close proximity to very bright sources. Post-calibration image processing and reconstruction methodologies, which he developed, uniquely tuned to NICMOS coronagraphic data, but generically applicable to high contrast imaging on other instrumental platforms, continue to be used by the EONS team and follow-on investigators in the analysis and interpretation of technically challenging observations and are yielding exceptional scientific results. Recent EONS discoveries of sculpted debris disks around young stars seen in scattered light may be explained by the dynamical influences exerted by unseen planetary-mass companions, and modeling of multi-wavelength SEDs (thermal IR, sub-mm, and mm) in concert with high contrast imaging elucidates the physical properties of the disk grains. Such imagery, indeed, provides a stepping-stone to answer the fundamental questions already posited. With the successful completion of the GTO observations, Dr. Schneider has continued in collaboration with many other NICMOS science team members in the reduction, calibration, analysis, and interpretation of data amassed during the accelerated observing program. He has actively lead, participated in, and contributed to a significant number of scientific investigations in collaboration with other team members and "outside" investigators, including follow-up programs to the NICMOS projects utilizing resources and facilities at Steward Observatory, Keck, Palomar, IRTF, Lick, and with other HST instruments. He has secured additional multi-wavelength follow-up observations to the NICMOS EONS programs as approved HST/GO programs and, additional observing time has been requesting for a more comprehensive surveys under the HST Cycle 13 call for proposals. Dr. Schneider, as a practitioner and advocate for space-based high-contrast imaging, has served the broader community interest through solicited investigatory studies such as his recent, widely distributed, report (issued by the the Space Telescope Science Institute, STScI) on the domains of observability in the near-IR with HST and ground-based AO systems, and with his service to the Congressionally requested Black committee report (and a source of input to the recent Bachall panel) on considerations of the scientific merit of an extended (then post-SM4) HST mission.

Functional Responsibilities and Experience as NICMOS Project Instrument Scientist. For more than nine years, as the NICMOS Project Instrument Scientist, Dr. Schneider saw the instrument through its final pre-launch design, implementation, integration and test, on-orbit calibration, science/operational, and post-mission recomissioning phases while taking on a number of pivotal leading and supervisory hardware, software, and programmatic responsibilities. The compression of the observational phase of the GTO program into a single HST observing cycle posed many unanticipated challenges in maintaining coherence in data calibration and analysis, as well as in reformulating many aspects of those investigations. In accomplishing the completion of those programs he worked with and for the NICMOS science team in many diverse aspects of planning (and replanning) GTO observations while continuing to serve as the Project's primary technical interface to the STScI, and Goddard Space Flight Center's (GSFC) codes 440, 441 and 512. During the pre-launch and commissioning phases of the NICMOS mission he worked closely with Ball Aerospace & Technology Corporation's (BATC) integrated product teams leading to the successful emergence of NICMOS as a facilities class instrument in the Hubble Space Telescope. His responsibilities have included frequent interaction with the aforementioned agencies in the development and implementation of ground and flight systems, procedures, software, interfaces, supporting on-orbit and ground calibration methodologies and data, on-orbit test procedures and detailed observing proposals to assure that the primary goals of NICMOS science programs were carried to successful conclusion. Concomitant with these activities were his daily interactions with software and technical support staff lending guidance and supervision on a diverse variety of team-support tasks. With the advent and rapid acquisition of NICMOS data, particularly in the coronagraphic programs that were enabled in the later phases of HST Cycle 7, his labors were successfully divided between science and functional support.

With the instruments' solid cryogen depletion, a significant portion of his efforts were devoted not only to post-mission calibration, characterization, and performance evaluation but in support of a large integrated systems engineering effort readying NICMOS for "resurrection" with the installation of an active cooling system (successfully installed on HST servicing mission 3B). In that regard, Dr. Schneider lead test teams both at the NICMOS Detector Laboratory at Steward Observatory and at the EMI/EMC facility at GSFC in conducting comprehensive experiments with a flight spare array replicating the on-orbit performance of the NICMOS detectors under on-orbit thermal conditions and integrated with the to-be-flown NICMOS cooling system. During that era his responsibilities extended to detailed end-to-end instrumental systems evaluations, in collaboration with GSFC and STScI personnel, in preparation for both serving mission (SM)3B and the Cycle 11 Observatory Verification (SMOV) program to follow, including leading the planning and analyses of key elements of the NICMOS recomissioning activities (e.g., detector performance, optical alignment and focus, target acquisition reactivation, etc.), which were  completed successfully as a precursor to re-enabling post-SM3B near-IR science on HST.

- Science Team Support. The complex process of developing viable observational strategies for carrying out near-IR astronomical investigations with HST did not relax as the mission evolved. Indeed, the rapid acceleration of the program demanded a closer and more detailed level of involvement in the monitoring, execution, and evaluation of observations than if the observing programs were played out over three cycles as originally envisioned. This was exacerbated with a new instrument whose characteristics were changing on short time scales. Dealing with this required vigilance in shepherding many of our needs through the "system", which Dr. Schneider attacked with success. He attributes this to the fact that he has worked closely in numerous aspects of HST operations and planning for nineteen years and, through trial-by-fire, has gained first-hand intimate knowledge of both the HST and NICMOS systems. Together these have afforded him the ability to assist team members, and the larger community of HST/NICMOS users, in dealing with unrelenting minutiae associated with the implementation of their scientific programs. He has seen this as a pivotal aspect of this position, and accordingly such activities have occupied much of his attention. Thus, he has directed his efforts toward making NICMOS as scientifically a productive instrument as possible (often, in the face of seemingly adversarial external forces to be overcome). The emergence of the continuing stream of NICMOS GTO and follow-on science, is demonstrative of his success in working toward that goal.

- Instrument Operations, Data Reduction, Processing and Analysis. Dr. Schneider continues to work on a daily basis as the UofA/IDT technical interface with STScI's PRESTO, CMD/ESB, Systems Engineering and NICMOS Instrument support groups. In addition to identifying and resolving proposal planning, execution, and instrument operations problems, he has recommended specific strategies to improve on-orbit efficiency, instrument stability and calibratability to expand the scope of NICMOS capabilities both in solid cryogen (Cycle 7) and NCC (Cycle 11 and beyond) eras. Such recommendations resulted from an expenditure of a considerable effort to understanding the on-orbit characteristics of NICMOS (as interfaced with HST) enabling the extraction of photometric and astrometric data from NICMOS images unbiased of systematic effects to the greatest extent possible. In doing so he has iterated many times with both STScI's NICMOS support group, and NICMOS Project software and database personnel, in improving calibration reference files as well as reduction and analysis software. He had also worked with STScI in planning for, and analyzing the results of the NICMOS warm-up in light of the concerns of an independent science review committee established by NASA (the Harwitt committee),  and for post SM-3B science operations. He assumed an active role in coordinating the "warm up anomaly" testing in the NICMOS detector lab based upon test goals discussed with the HST Project at GSFC and STScI as well as the responsibility for supervising the integrated test team and laboratory personnel.

- Pre-launch Instrument Calibration (SLTV, RAS/HOMS, EMI/EMC testing). To explore and evaluate the operating characteristics of NICMOS, Dr. Schneider took a leading role in the definition, execution and analysis of the pre-launch calibration programs at BATC. Working closely during round-the-clock shifts with BATC project management, hardware, S/W, and test team personnel he investigated anomalous behaviors, which led to both a better understanding of the instrument, and changes in the methods and philosophy of instrument operation.

- HST Systems Level Integration, Test, and Verification (VEST, STOCC), SOGS/SPSS. The exercise of pre-deployment validation of a new HST science instrument required extensive sub-system and integrated tests to be run with both ground and flight hardware and software. Dr. Schneider supported these efforts by defining, contributing to, and participating in numerous ground system and functional tests (unit and end-to-end) and simulations. To validate the command generation capability of the HST ground system for NICMOS, and the response to those command requests by the instrument, he worked with STScI ESB/Commanding personnel in creating test proposals, calendars, and Science Mission Specifications used in these series of tests and subsequently analyzed resulting image data and engineering telemetry. He worked with BATC I&T and MOSES SI/SE personnel in reviewing Real-Time command and operations procedures required for these tests and in preparation for flight. In addition, he monitored and evaluated the ground system and instrument behavior during test execution, and participated in real-time hardware and software anomaly analysis and resolution.

- SM-2 and SM-3B On-Orbit Instrument Checkout (AT/FT Planning and Execution). Dr. Schneider was an active member of the SM-2 and 3B flight preparation and operations teams defining and improving procedures for the NICMOS on-orbit installation and checkout. He participated in defining the NICMOS requirements and implementation details of the Servicing Missions Integrated Timeline, Command Plan, on-orbit Aliveness and Functional tests, developed evaluation/acceptance criteria and real-time analysis S/W for the latter. This included on-console at the STOCC for all SMGTs, JISs, and during the mission as the IDT science support representative.

- SM OV 2 and 3B Program Planning, Implementation, and Analysis. Dr. Schneider served (and continues to serve) as the UofA/IDT representative and technical lead for the NICMOS Servicing Mission Observatory Verification programs. This engendered defining the NICMOS SMOV plans and requirements in concert with HST and STScI project management. As Principle Investigator for many of the SMOV programs (and co-I on most others), he developed and implemented on-orbit check-out, engineering, and calibration proposals, operations procedures and analysis plans in consultation and association with STScI and the BATC I&T teams. Post-launch he worked extensively at STScI to support near-RT analysis and a dynamically evolving and changing SMOV program in light of unexpected instrumental performance anomalies.

Research Activity Funding - Hubble Space Telescope / NASA

Recent Awarded GO/AR Science Funding as P.I. at Steward Observatory

Title:         A Search for Stellar Duplicity and Variability
               from FGS Guide Star Acquisitions and Guiding Data
Program:       HST-AR-05811
Start Date:    04/01/1995
Closeout Date: 10/15/1999
Funds Awarded: $44,378 

Title:         Direct Imaging of a Circumstellar Disk: Beta
               Pictoris, a Case Study
Program:       HST-GO-06058
Start Date:    09/01/1995
Closeout Date: 09/30/1999
Funds Awarded: $9,921

Title:         Near-IR Photometry of a Candidate companion to
               Proxima Centauri
Program:       HST-GO-07847
Start Date:    11/01/1998
Closeout Date: 06/25/2001
Funds Awarded: $11,296

Title:         Confirmation and Charactization of Brown Dwarfs
               and Giant Planets from NICMOS 7226/7667
Program:       HST-GO-08176
Start Date:    09/01/1999
End Date:      08/31/2003
Funds Awarded: $116,976 ($69,092 to UofA)

Title:         Duplicity and Variability in HST Guide Stars ?
               An FGS Serendipitous Survey
Program:       HST-AR-08730
Start Date:    02/01/1999
Closeout Date: 07/18/2002
Funds Awarded: $53,165 ($39,615 to UofA)

Title:         Imaging and Spectroscopy of Dusty Circumstellar
Program:       HST-GO-08624
Start Date:    11/01/2000
Closeout Date: 10/31/2003
Funds Awarded: $32,738

Title:         Enabling Coronagraphic Polarimetry with NICMOS
Program:       HST-GO-09768
Start Date:    10/05/2003
Closeout Date: 10/15/2004
Funds Awarded: $29,400

Title:         Coronagraphic Survey for Giant Planets Around Nearby
               Young Stars
Program:       HST-GO-10176
Start Date:    09/01/2004
Closeout Date: 08/31/2009
Funds Awarded: $102,900

Title:         Imaging Ices in Circumstellar Disks
Program:       HST-GO-10167
Start Date:    03/01/2005
Closeout Date: 02/28/2007
Funds Awarded: $41,727

Title:         Solar Systems in Formation: A NICMOS Corongarphic
               Survey of Protoplanetary and Debris Disks
Program:       HST-GO-10177
Start Date:    07/01/2004
Closeout Date: 06/30/2009
Funds Awarded: $497,504 ($347,450 to UofA)

Title:         Imaging Polarimetry of Young Stellar Objects with ACS
               and NICMOS: A Study in Dust Grain Evolution
Program:       HST-GO-10178
Start Date:    11/01/2004
Closeout Date: 10/30/2008
Funds Awarded: $46,552

Title:         Imaging Scattered Light from Debris Disks Descovered by the
               Spitzer Space Telescope Around 20 Sun-like Stars
Program:       HST-GO-10527
Start Date:    09/01/2005
Closeout Date: 03/31/2009
Funds Awarded: $173,911

Title:         Near-IR Spectrophotometry of 2MASSWJ 1207334-393254B -
               An Extra-Solar Planetary Mass Companion to a Young Brown Dwarf
Program:       HST-GO-10538
Start Date:    05/01/2005
Closeout Date: 06/30/2009
Funds Awarded: $155,862 ($136,989 to UofA)

Title:         The NICMOS Polarimetric Calibration
Program:       HST-GO-10839
Start Date:    09/01/2006
Closeout Date: 8/31/2009
Funds Awarded: $44,363

Title:         Coronagraphic Polarimetry of HST-Resolved Debris Disks
Program:       HST-GO-10847
Start Date:    09/01/2006
Closeout Date: 08/31/2009
Funds Awarded: $69,461

Title:         Imaging Scattered Light from Debris Disks Discovered by
               the Spitzer Space Telescope around 21 Sun-like Stars

Program:       HST-GO-10849
Start Date:    07/01/2006
Closeout Date: 06/30/2009
Funds Awarded: $220,222

Title:         Coronagraphic Polarimetry with NICMOS: Dust Grain
               Evolution in T Tauri Stars

Program:       HST-GO-10852
Start Date:    09/01/2006
Closeout Date: 08/31/2009
Funds Awarded: $141,824 ($55,775 to UofA)

Title:         Mapping the Gaseous Content of Protoplanetary and Young
               Planetary Systems with ACS

Program:       HST-GO-10864
Start Date:    05/01/2007
Closeout Date: 04/30/2009
Funds Awarded: $47,346

Title:         A Paschen-Alpha Study of Massive Stars and the ISM in the
               Galactic Center
Program:       HST-GO-11120
Start Date:    05/01/2008
Closeout Date: 04/30/2010
Funds Awarded: $19,105

Title:         Dust Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging
               and Polarimetry
Program:       HST-GO-11155
Start Date:    09/01/2007
Closeout Date: 08/31/2009
Funds Awarded: $87,354

Title:         NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the
               Stellar Mass
Program:       HST-GO-11157
Start Date:    09/01/2007
Closeout Date: 08/31/2009
Funds Awarded: $147,624

Title:         A Legacy Archive PSF Library and Circumstellar Environments
               (LAPLACE) Investigation

Program:       HST-AR-11279
Start Date:    07/01/2007
Closeout Date: 07/31/2009
Funds Awarded: $381,981 ($161,436 to UofA)

Title:         A STIS NUV Search for Shocked-Interstellar and Circumstellar Gas
               Towards the Debris System HD 61005

Program:       HST-GO-11674
Start Date:    Pending Data Acquisition
Closeout Date: Pending Data Acquisition
Funds Awarded: $19,646

Title:         Structure and Chemestry of Planet-Building Disks: A Synoptpic Study
Program:       NASA 08-ADP08-0036
Start Date:    07/01/2009
Closeout Date: 06/30/2010
Funds Awarded: $4,895

HST GO, GTO, AR Program Summaries as Principal or Co- Investigator

A STIS NUV Search for Shocked-Interstellar and Circumstellar Gas Towards the Debris System HD 61005: co-I/GO (11674).  Circumstellar debris disks provide the principle window for investigating planet formation and evolution on timescales of 10-100 Myr. Unlike their younger counterparts, debris disks no longer contain primordial material. The dust observed in these objects is instead produced by collisional erosion of larger parent bodies in the developing planetary system. Currently, only five confirmed debris disks have detected circumstellar gas, studied primarily through UV absorption spectroscopy.  The exact production mechanisms for this replenished gas are presently poorly constrained. However, the few objects studied so far have revealed a wide range of intruiging properties, including a stable Keplerian gas disk maintained by its high carbon abundance (Beta Pic), and a rapidly expelled population of gas produced in collisions between unstable planetesimals (Sigma Her). To add to this important set of observations, we propose to obtain NUV STIS spectroscopy of the debris disk host, HD 61005, a nearly edge-on debris disk notable for its swept asymmetric morphology. These observations allow the likely detection of circumstellar gas, making HD 61005 the first solar-type debris disk host with gas detected in this way. Thus, the     
proposed observations provide the unique opportunity to study gas in a debris disk analogous to our early solar system. In addition to potentially detecting circumstellar gas associated with this system, HD 61005 offers the possibility of tracing interstellar bow-shocked gas. HD 61005 is a unique debris disk in terms of its significant interaction with the interstellar medium. The proposed observations
will, therefore, be the first to directly probe the interaction between a debris disk and its surrounding interstellar material. STIS is ideally suited for this experiment, providing sensitive NUV spectra with the required balance between spectral resolution and wavelength coverage.

A Legacy Archive PSF Library And Circumstellar Environments LAPLACE Investigation, PI/AR (11279). 
NICMOS coronagraphy, with well-matched template Point Spread Function (PSF) subtraction, probes the closest environments of occulted targets with the highest imaging sensitivity in intrinsically high contrast fields at the smallest radial distances afforded, uniquely, by HST. NICMOS PSF-subtracted coronagraphy has been\ invoked in a wide variety of HST programs with science themes as divergent as detecting and characterizing disks of circumstellar material in neo-natal stellar environments, to studying faint nebulosity associated with luminous active galaxies, to searching for planetary-mass companions in extrasolar planetary systems recently born and in the "stellar graveyard." The investment in HST time in the execution of these and other programs, which has resulted in more than 8450 NICMOS coronagraphic images to date, has met with mixed returns. Stunning (but infrequent) successes, importantly advancing their fields highlight much more frequent, unfortunately common, failures arising from highly compromised technically-achievable performance due to the lack of suitable template PSFs required to produce high-fidelity, photometrically robust, high contrast coronagraphic images. We propose to remedy this situation by undertaking a rigorous, homogeneous, and complete recalibration and analysis of the full archival set of raw NICMOS coronagraphic images previously obtained and residing in the MAST to create a Legacy library of template PSFs enabling the recovery of the large body of science otherwise lost. This PSF library, along with generically applicable analysis software that we will deliver to STScI, will: (1) critically augment the needs of future observational programs reliant on highfidelity PSF subtractions, (2) increase their yields and photometric efficacy, (3) reduce the observing time (HST orbit allocations) otherwise required for near-contemporaneous reference PSF observations, and (4) greatly enrich the yet-unrealized potential of the many NICMOS coronagraphic observations already acquired from the broad spectrum of science programs previously executed. We will then use the enabling power of the PSF library to re-reduce and re-analyze all archival NICMOS coronagraphic observations of circumstellar disk and VLM stellar, brown dwarf, and EJP companion candidate stars (~ 400 targets) to probe for previously undetected circumstellar disks. Through image analysis and modeling we will ascertain the physical properties of newly-discovered disks and their constituent grains. With a very large and homogeneously contrast-limited sample of optimally PSF-subtracted images, we will also set spatially resolved dust-scattered light flux density limits from non-detections to constrain the properties of the many IR-excess (and other) sources in this sample.

NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the Stellar Mass Spectrum, co-I/GO (11157). 
Association of planetary systems with dusty debris disks is now quite secure, and advances in our understanding of planet formation and evolution can be achieved by the identification and characterization of an ensemble of debris disks orbiting a range of central stars with different masses and ages. Imaging debris disks in starlight scattered by dust grains remains technically challenging so that only about a dozen systems have thus far been imaged. A further advance in this field needs an increased number of imaged debris disks. However, the technical challege of such observations, even with the superb combination of HST and NICMOS, requires the best targets. Recent HST imaging investigations of debris disks were sample-limited not limited by the technology used. We performed a search for debris disks from a IRAS/Hipparcos cross correlation which involved an exhaustive background contamination check to weed out false excess stars. Out of ~140 identified debris disks, we selected 22 best targets in terms of dust optical depth and disk angular size. Our target sample represents the best currently available target set in terms of both disk brightness and resolvability. For example, our targets have higher dust optical depth, in general, than newly identified Spitzer disks. Also, our targets cover a wider range of central star ages and masses than previous debris disk surveys. This will help us to investigate planetary system formation and evolution across the stellar mass spectrum. The technical feasibility of this program in two- gyro mode guiding has been proven with on-orbit calibration and science observations during HST cycles 13, 14, and 15.

Dust Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging and Polarimetry, co-I/GO (11155). 
We are taking advantage of the sensitive coronagraphic capabilities of NICMOS to obtain multiwavelength coronagraphic imaging and polarimetry of primordial dust disks around young intermediate-mass stars (Herbig Ae stars), in order to advance our understanding of how dust grains are assembled into larger bodies. Because the polarization of scattered light is strongly dependent on scattering particle size and composition, coronagraphic imaging polarimetry with NICMOS provides a uniquely powerful tool for measuring grain properties in spatially resolved circumstellar disks. It is widely believed that planets form via the gradual accretion of planetesimals in gas-rich, dusty circumstellar disks, but the connection between this suspected process and the circumstellar disks that we can now observe around    other stars remains very uncertain. Our proposed observations, together with powerful 3-D radiative transfer codes, will enable us to quantitatively determine dust grain properties as a function of location within disks, and thus to test whether dust grains around young stars are in fact growing in size during the putative planet-formation epoch. HST imaging polarimetry of Herbig Ae stars will  complement and extend existing polarimetric studies of disks around lower-mass T  Tauri stars and debris disks around older main-sequence stars. When combined with these previous studies, the proposed research will help us establish the influence of stellar mass on the growth of dust grains into larger planetesimals, and ultimately to planets. Our results will also let us calibrate models of the thermal emission from these disks, a critical need for validating the properties of more
distant disks inferred on the basis of spectral information alone.

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center, co-I/GO (11120). The Galactic center (GC) is a unique site for a detailed study of a multitude of complex astrophysical phenomena, which may be common to nuclear regions of many galaxies. Observable at resolutions unapproachable in other galaxies, the GC provides an unparalleled opportunity to improve our understanding of the interrelationships of massive stars, young stellar clusters, warm and hot ionized gases, molecular clouds, large scale magnetic fields, and black holes. We propose the first large-scale hydrogen Paschen alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This survey will lead to a high resolution and high sensitivity map of the Paschen alpha line emission in addition to a map of foreground extinction, made by comparing Paschen alpha to radio emission. This survey of the inner 75 pc of the Galaxy will provide an unprecedented and complete search for sites of massive star formation. In particular, we will be able to (1)  uncover the distribution of young massive stars in this region, (2) locate the surfaces of adjacent molecular clouds, (3) determine important physical parameters   of the ionized gas, (4) identify compact and ultra-compact HII regions throughout the GC. When combined with existing Chandra and Spitzer surveys as well as a wealth of other multi-wavelength observations, the results will allow us to address such questions as where and how massive stars form, how stellar clusters are disrupted,  how massive stars shape and heat the surrounding medium, and how various phases of   this medium are interspersed.

Mapping the Gaseous Content of Protoplanetary and Young Planetary Systems with ACS, co-I/AR (10864). One of the key problems in planetary system formation is understanding how rapidly, and over what time interval Jovian planets can form. Dust in the protoplanetary disk is critical in planetesimal formation, but it is the gas which produces giant planets, and which is essential for their migration. However, compared to data on the circumstellar dust, information on the gas component is sparse, especially in the planet-formation zone. This severely limits our ability to put observational constraints on giant planet formation, except to note that the process must be largely complete by 12 Myr, given the paucity of Herbig Ae or classical T Tauri stars older than 10-12 Myr. In the FUV, photo-excited molecular hydrogen transitions have the requisite contrast to the stellar photosphere, accretion shock, and reflection nebulosity, and can be traced 50-100 AU from the exciting stars in both envelopes and outflow cavities and protoplanetary disks. Central disk cavities, an expected consequence of planet formation, larger than 0.1" are directly detectable in HST FUV spectra, while smaller cavities may be detected by comparison with protoplanetary disks which are still accreting onto their stars. We propose augmenting existing HST coronagraphic imagery of 6 Herbig Fe and T Tauri disks with ACS Solar-Blind Channel Lyman alpha imagery and slitless spectroscopy simultaneously sampling the disk in molecular hydrogen and small-grain reflection nebulosity. These data will be used to quantify the amount of vertical stratification in these disks, to map the mass-loss geometry from the star, and to determine whether removal of molecular material preceeds, lags, or is contemporary with clearing of the dust.

Coronagraphic Polarimetry with NICMOS: Dust Grain Evolution in T Tauri Stars, PI/GO (10852).
The formation of planetary systems is intimately linked to the dust population in circumstellar disks, thus understanding dust grain evolution is essential to advancing our understanding of how planets form. By combining (1) the coronagraphic polarimetry capabilities of NICMOS, (2) powerful 3-D radiative transfer codes, and (3) observations of objects known to span the Class II-III stellar evolutionary phases, we will gain crucial insight into dust grain growth. By observing objects representative of a known evolutionary sequence of YSOs, we will be able to investigate how the dust population evolves in size and distribution during the crucial transition from a star+disk system to a system containing planetesimals. When combine with our previous study on dust grain evolution in the Class I-II phase, the proposed study will help to establish the fundamental time scales for the depletion of ISM-like grains: the first step in understanding the transformation from small submicron sized dust grains, to large millimeter sized grains, and untimely to planetary bodies.

Coronagraphic Polarimetry of HST-Resolved Debris Disks, co-I/GO (10847).  We take full advantage of the recently commissioned coronagraphic polarimetry modes of ACS and NICMOS to obtain imaging polarimetry of circumstellar debris disks that were imaged previously by the HST coronagraphs, but without the polarizers. It is well established that stars form in gas-rich protostellar disks, and that the planets of our solar system formed from a circum-solar disk. However, the connection between the circumstellar disks that we observe around other stars and the processes of planet formation is still very uncertain. Mid-IR spectral studies have suggested that disk grains are growing in the environments of young stellar objects during the putative planet-formation epoch. Furthermore, structures revealed in well resolved images of circumstellar disks suggest gravitational influences on the disks from co-orbital bodies of planetary mass. Unfortunately, existing imaging data provides only rudimentary information about the disk grains and their environments. Our proposed observations, which can be obtained only with HST, will enable us to quantitatively determine the sizes of the grains and optical depths as functions of their location within the disks (i.e., detailed tomography). Armed with these well-determined physical and geometrical systemic parameters, we will develop a set of self-consistent models of disk structures to investigate possible interactions between unseen planets and the disks from which they formed. Our results will also calibrate models of the thermal emission from these disks, that will in turn enable us to infer the properties of other debris disks that cannot be spatially resolved with current or planned instruments and telescopes.

The NICMOS Polarimetric Calibration, co-I/GO (10839).
Recently, it has been shown that NICMOS possesses an instrumental polarization at a level of 1.2%. This completely inhibits the data reduction in a number of previous GO programs, and hampers the ability of the instrument to perform high accuracy polarimetry. In all, 90 orbits of HST data are affected, with potentially many more in Cycle 15. We propose to obtain high signal to noise observations of three polarimetric standards at the cardinal roll angles of the NICMOS polarizers for both NIC1 and NIC2. These observations are designed to fully characterize the instrumental polarization in order for NICMOS to reach its full potential by enabling high accuracy polarimetry of sources with polarizations around 1%. The residual polarization will also be determined as a function of position and spectral energy distribution. Our group will rapidly turn around the required data products and produce reports and software for the accurate representation of the instrumental polarization. These items will be presented to STScI for dissemination among the wider astronomical community.

Imaging Scattered Light from Debris Disks Discovered by the Spitzer Space Telescope around 21 Sun-like Stars, co-I/GO (10849). 
A programmatic follow-on to GO/10527. We use the high-contrast capability of the NICMOS coronagraph to image a sample of newly discovered circumstellar disks associated with Sun-like stars. These systems were identified by their strong thermal infrared (IR) emission with the Spitzer Space Telescope as part of the Spitzer Legacy Science program titled "The Formation and Evolution of Planetary Systems" (FEPS, P.I.: M.Meyer). Modeling of the thermal excess emission from the spectral energy distributions alone cannot distinguish between narrowly confined high-opacity disks and broadly distributed, low-opacity disks. By resolving light scattered by the circumstellar material, our proposed NICMOS observations can break this degeneracy, thus revealing the conditions under which planet formation processes are occuring or have occured. For three of our IR-excess stars that have known radial-velocity planets, resolved imaging of the circumstellar debris disks may further offer an unprecedented view of planet-disk interactions in an extrasolar planetary system. Even non-detections of the light scattered by the circumstellar material will place strong constraints on the disk geometries, ruling out disk models with high optical depth. Unlike previous disk imaging programs, our program contains a well-defined sample of ~1 solar mass stars covering a range of ages from 3 Myr to 3 Gyr, thus allowing us to study the evolution of disks from primordial to debris for the first time. The results from our program will greatly improve our understanding of the architecture of debris disks around Sun-like stars, and will create a morphological context for the existence of our own solar system.

Mapping the Gaseous Content of Protoplanetary and Young Planetary Systems with ACS, co-I/GO (10864). One of the key problems in planetary system formation is understanding how rapidly, and over what time interval Jovian planets can form. Dust in the protoplanetary disk is critical in planetesimal formation, but it is the gas which produces giant planets, and which is essential for their migration. However, compared to data on the circumstellar dust, information on the gas component is sparse, especially in the planet-formation zone. This severely limits our ability to put observational constraints on giant planet formation, except to note that the process must be largely complete by 12 Myr, given the paucity of Herbig Ae or classical T Tauri stars older than 10-12 Myr. In the FUV, photo-excited molecular hydrogen transitions have the requisite contrast to the stellar photosphere, accretion shock, and reflection nebulosity, and can be traced 50-100 AU from the exciting stars in both envelopes and outflow cavities and protoplanetary disks. Central disk cavities, an expected consequence of planet formation, larger than 0.1" are directly detectable in HST FUV spectra, while smaller cavities may be detected by comparison with protoplanetary disks which are still accreting onto their stars. We propose augmenting existing HST coronagraphic imagery of 6 Herbig Fe and T Tauri disks with ACS Solar-Blind Channel Lyman alpha imagery and slitless spectroscopy simultaneously sampling the disk in molecular hydrogen and small-grain reflection nebulosity. These data will be used to quantify the amount of vertical stratification in these disks, to map the mass-loss geometry from the star, and to determine whether removal of molecular material preceeds, lags, or is contemporary with clearing of the dust.

Near-IR Spectrophotometry of 2MASSWJ 1207334-393254B - An Extra-Solar Planetary Mass Companion to a Young Brown Dwarf, PI/GO (10538). 
We propose to obtain "short" wavelength near-IR diagnostic and characterizing spectra of the very high probability candidate extra-solar giant planet (EGP) companion to 2MASSWJ 1207334-393254 (2M1207), a young brown dwarf and TW Hydrae Association member. Recent NICMOS camera 1 multi-band photometric imaging of the companion candidate, 0.77" (54 AU projected) from 2M1207 - initially detected at longer wavelengths with VLT/NACO - implicate an object of several Jupiter masses based on cooling models of EGPs and the likely age of 2M1207 (~ 8 Myr). Physical companionship of the EGP candidate with 2M1207 has been established at the 99.1% level of confidence via second-epoch NICMOS astrometric observations. Diagnostic spectra in the 0.8 to 1.9 micron region (unobtainable from the ground and overlapping the NICMOS imaging observations) will (a) critically inform on the physical nature of the EGP, (b) provide currently non-existing information to test/constrain theoretical models of EGP properties and evolution, and (c) unequivocally confirm the imaging of a bone fide EGP. Background light from 2M1207 would normally swamp the EGP spectrum with direct spectral imaging. To obviate this, we propose PSF-subtracted grism spectra of the EGP using 2M1207 as its own spectral template via two-orientation high-contrast image subtraction. The temporal stability of the HST+NICMOS PSF enables self-subtractions of targets at different field orientations resulting in contrast enhancements of 5 to 6 stellar magnitudes in the circumstellar background at ~ 0.8" at these wavelengths. With the grism field oriented to place the EGP "above" and "below" 2M1207 (at two observational epochs)
two independent spectra of the EGP will emerge from a difference image. This prototypical spectrum will serve to test and improve upon current models of young EGPs which predict flux suppression by molecular absorption in their atmospheres.

Imaging Scattered Light from Debris disks Discovered by the Spitzer Space Telescope Around 20 sun-like Stars, co-I/GO (10527).  We propose to use the high contrast capability of the NICMOS coronagraph to image a sample of newly discovered circumstellar disks associated with sun-like stars. These systems were identified by their strong thermal infrared emission with the Spitzer Space Telescope as part of the Spitzer Legacy Science program titled, "The Formation and Evolution of Planetary Systems (FEPS)." Modelling of the thermal excess emission in the form of spectral energy distributions alone cannot distinguish between narrowly confined high opacity disks and broadly distributed, low opacity disks. However, our proposed NICMOS observations can, by imaging the light scattered from this material. Even non- detections will place severe constraints on the disk geometry, ruling out models with high optical depth. Unlike previous disk imaging programs, our program contains a well defined sample of solar mass stars covering a range of ages from ~10Myrs to a few Gyrs, allowing us to study the evolution of disks from primordial to debris for the first time. These results will greatly improve our understanding of debris disks around Sun-like stars at stellar ages nearly 10x older than any previous investigation. Thus we will have fit a crucial piece into the puzzle concerning the formation and evolution of our own solar system.

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A Study in Dust Grain Evolution, co-I (10178). 
The formation of planetary systems is intimately linked to the dust population in circumstellar disks, thus understanding dust grain evolution is essential to advancing our understanding of how planets form. By combining (1) the high resolution polarimetric capabilities of ACS and NICMOS, (2) powerful 3-D radiative transfer codes, and (3) observations of objects known to span the earliest stellar evolutionary phases, we will gain crucial insight into the initial phases of dust grain growth: evolution away from an ISM distribution. Fractional polarization is a strong function of wavelength, therefore by comparing polarimetric images in the optical and infrared, we can sensitively constrain not only the geometry and optical depth of the scattering medium, but also the grain size distribution. By observing objects representative of the earliest evolutionary sequence of YSOs, we will be able to investigate how the dust population evolves in size and distribution during the crucial transition from a disk+envelope system to a disk+star system. The proposed study will help to establish the fundamental time scales for the initial depletion of ISM-like grains: the first step in understanding the transformation from small submicron sized dust grains, to large millimeter sized grains, and untimely to planetary bodies.

Coronagraphic Survey for Giant Planets Around Nearby Young Stars, co-I (10176).
A systematic imaging search for extra-solar Jovian planets is now possible thanks to recent progress in identifying "young stars near Earth". For most of the proposed young (<~ 30 Myrs) and nearby (<~ 60 pc) targets, we can detect a few Jupiter-mass planets as close as a few tens of AUs from the primary stars. This represents the first time that potential analogs of our solar system - that is planetary systems with giant planets having semi-major axes comparable to those of the four giant planets of the Solar System - come within the grasp of existing instrumentation. Our proposed targets have not been observed for planets with the Hubble Space Telescope previously. Considering the very successful earlier NICMOS observations of low mass brown dwarfs and planetary disks among members of the TW Hydrae Association, a fair fraction of our targets should also turn out to posses low mass brown dwarfs, giant planets, or dusty planetary disks because our targets are similar to (or even better than) the TW Hydrae stars in terms of youth and proximity to Earth. Due to the recent cancellation of SM4, HST will inevitably degrade into a 2-gyro mode soon and high contrast survey programs like our own cannot be carried out with two gyros. This means that the HST cycle 13 may be the last chance to find young Solar System analogs in the coming decade. Should HST time be awarded and planetary mass candidates be found, proper motion follow-up of candidate planets will be done with ground-based AOs.

Imaging of Ices in Circumstellar Disks, co-I (10167).
The link between the material of the interstellar medium and the ultimate composition of planets lies in the way gas and dust are processed in circumstellar
disks. Planet formation models rely upon a knowledge of the disk constituents and temperature profiles to simulate how small grains eventually combine into terrestrial planets and gas giant cores. Disks around other stars may be analogs for our own early Solar System and thus allow the direct measurement of such phenomena. Only recently, however, have well-resolved images of dust disks around several late T Tauri or main sequence stars been secured. HST provides a uniquely stable platform for making such sensitive high dynamic range images. Now, for those handful of disks already resolved, we are able to go beyond the discovery phase and begin making astrophysical measurements to deepen our understanding of the course of disk evolution. We therefore propose a multi-wavelength study with NICMOS designed to discover the spatial distribution of two common Solar System materials -- methane and water ices -- in other systems.

Spatially Resolved Spectroscopy of HR 4796A's Dust Ring, co-I (10168). 
HST's high-contrast capabilities provide exciting imaging of circumstellar debris disks with complex structures. In particular, broad-band imaging using the coronagraphs in NICMOS and STIS has elucidated the disk morphology of HR 4796A exquisitely, but can only provide colors, not detailed compositional information on its dust. With spectra, we will measure the detailed albedo of the disk dust over a large wavelength range and search for interstellar medium-like molecules and water ice. We will also use our spatially resolved spectra for very high angular resolution profiles of the disk width to constrain models for planets circling inside the dust. We have demonstrated in a previous program how to use STIS for spatially resolved disk spectroscopy. We now propose to use our technique to study HR 4796A. This program was, of necessity, withdrawn due to the fatal failure of the Space Telescope Imaging Spectrograph before the approved observations were executed.

Solar systems in Formation: A NICMOS Coronagraphic Survey of Protoplanetary and Debris Disks, PI/GO (10177). 
Until recently, despite decades of concerted effort applied to understanding the formation processes that gave birth to our solar system, the detailed morphology of circumstellar material that must eventually form planets has been virtually impossible to discern. The advent of high contrast, coronagraphic imaging as implemented with the instruments aboard HST has dramatically enhanced our understanding of natal planetary system formation. Even so, only a handful of evolved disks (~ 1 Myr and older) have been imaged and spatially resolved in light scattered from their constituent grains. To elucidate the physical processes and properties in potentially planet-forming circumstellar disks, and to understand the nature and evolution of their grains, a larger spatially resolved and photometrically reliable sample of such systems must be observed. Thus, we propose a highly sensitive circumstellar disk imaging survey of a well-defined and carefully selected sample of YSOs (1-10 Myr T Tau and HAeBe stars) and (> app 10 Myr) main sequence stars, to probe the posited epoch of planetary system formation, and to provide this critically needed imagery. Our resolved images will shed light on the spatial distributions of the dust in these thermally emissive disks. In combination with their long wavelength SEDs the physical properties of the grains will be discerned, or constrained by our photometrically accurate surface brightness sensitivity limits for faint disks which elude detection. Our sample builds on the success of the exploratory GTO 7233 program, using two-roll per orbit PSF-subtracted NICMOS coronagraphy to provide the highest detection sensitivity to the smallest disks around bright stars which can be imaged with HST. Our sample will discriminate between proposed evolutionary scenarios while providing a legacy of cataloged morphologies for interpreting mid- and far-IR SEDs that the recently launched Spitzer Space Telescope will deliver. This project cannot be done from the ground, and becomes untenable for HST after Cycle 13 under the anticipated use of two-gyro pointing control mode.

Imaging and Spectroscopy of Dusty Circumstellar Disks, co-I/GO (8624)
. Understanding the properties and evolution of dusty disks in the circumstellar environments of young stars is a key element in furthering our concepts of the formation mechanisms of extra-solar planetary systems. The advent of NICMOS and STIS coronagraphy has given rise to the first scattered light imaging, other than for Beta Pictoris, of dusty circumstellar disks with spatially resolved morphological structures. NICMOS has taken a first step in imaging these new disks, elucidating their geometries, morphologies, and bulk photometric properties, while increasing the number of such known systems from one to half a dozen. These dusty disks vary in physical size by over two orders of magnitude and exhibit radial anisotropies in their brightness distributions that may be indicative of dynamical confinement or sculpting of the disk particles by unseen planetary bodies. STIS follow-on imaging and spectroscopy are needed to provide further insight into the nature of the disk particles. With spectra, the albedo of the disk dust is measured and signatures of complex molecules and water ice are sought. With coronagraphic images, the scattering phase function and hence the composition of the disk dust is investigated in concert with direct determination of the disk sizes and shapes with high precision. Such observations are of fundamental importance in establishing the physical basis for emergent theories of disk evolution and planet-building.

Imaging the Dust Disk around Epsilon Eridani, co-I/GO (9037). Epsilon Eridani is the closest star to the Sun around which a planet has been discovered. An asymmetric dust disk around the star has been detected in sub-millimeter observations. Clumps in the disk have been interpreted as resulting from resonant interaction, and the pattern has been predicted to revolve around star at a rate of ~ 0.7° per year. Multi-epoch observations of the dust disk with STIS will obtained. These observations will not only reveal what may be the first extra-solar Kuiper belt, but will also provide a crucial step in the development of observational techniques that can determine the presence and properties of planets, from the visible morphology of the disks around the parent stars.

Confirmation and Characterization of Brown Dwarfs and Giant Planets from NICMOS 7226/7227, P.I./GO (8176): A selected candidate list of 74 stars was observed using the NICMOS coronagraph at 1.6 mm. Eight companion candidate objects as faint as H = 20, up to 13 magnitudes fainter than their primaries with separations less than 5" were found (and a majority subsequently confirmed as low mass companions by common  proper motions). For the stars in this sample this covers minimum physical separations of 1.2-50 AU at the inner spatial detection limit. The lower mass limit depends on age, distance, and spectral type, but is as low as 3-5 MJupiter for many of the program targets. Spectrographic observations are essential to characterize the physical nature of the putative companions we have discovered. These observations address fundamental questions such as: Is there a continuity of objects across the substellar mass spectrum bridging the main sequence to planetary objects? What is their frequency of occurrence? At what distances are they found from their primaries? And, what implications will these discoveries have for our understanding of stellar/planetary formation mechanisms?

A Search for Low Mass/Sub-Luminous Companions to M-Stars, PI/GTO (7227): Knowledge of stellar and sub-stellar masses and luminosities at and below the ~ 0.08 Msun Hydrogen burning limit is of fundamental importance in many inter-related areas such as probing the end of the stellar mass function, the theory of stellar evolution, the end of the main sequence, the galactic missing mass, age and evolution. Yet, this transition region in the mass spectrum of objects between low-mass stars and giant planets is poorly understood and ill-observed. Until very recently, with the discovery of the Brown Dwarf companion to GL 229, the very existence of such objects remained in the conjectural realm. To make further progress in low end of the mass distribution function, additional objects first must be found. Potentially fruitful hunting-grounds to search for such transitional objects using NICMOS, in parameter spaces which do not overlap with ground-based capabilities, are as companions to M-dwarfs which are: Nearby (d < 6 pc) and spectral types later than ~ M3.5; Young (? 108 years) and at d ? 25 pc.; and Spectrally the latest known (> ~ M8.5). This investigation carries out a coronagraphic imaging program aimed at discovering such objects.

A Search for Massive Jupiters. Co-I/GTO (7226): NICMOS is used to search for massive planets around nearby, young main sequence stars. Camera 2 and the coronagraph is employed to search from 0.3" to 3" at the wavelength band of 1.4 ? 1.8 mm (F160W) which corresponds to strong emission in the brown dwarf candidates GL 229B and GD 165B as well as to strong reflections in Jupiter and Titan. Because of the extreme youth of these objects, any low-mass brown dwarf and planetary companions will still be in a higher luminosity phase and thus easily detectable. The lower mass limit depends on age, distance, and spectral type, but can be as low as 3 ? 5 Mjupiter for targets in our sample. Follow-up observations of candidate companions will provide proof of true physical association with the primary. The typical separations observable with NICMOS are near the empirical maximum in the binary distribution of stars (~ 20 ? 40 AU), which also corresponds to the mean distance of the giant planets in our own solar system.

Dust Disks Around Main Sequence Stars. Co-I/GTO (7233): A selection of mostly main sequence stars which have (a) tdust > 10-3 or (b) other characteristics that suggest the presence of circumstellar dust disks is observed. The observations will be made with the coronagraph to minimize the effects of glare from the bright central star. We dither the pointing by means of a spacecraft roll for best background subtraction. As a primary objective, all images will be examined for the presence of dust disks. An important secondary objective is a search of all images for possible brown dwarfs or high-mass planets. If detections are made, additional observations will be attempted to characterize the physical properties of those objects found.

(Spectroscopy and) Polarimetry of the Beta Pictoris Disk, Co-I/GTO (7248): Little is known about the b Pictoris disk within 50 AU of the central star. No near-infrared spectrophotometry or polarimetry exists within this dynamically interesting region, which is about the same size as our own solar system and which appears to be relatively depleted of disk material. Grism spectroscopy (R ~ 75)  and polarimetry of the disk from within 5 AU of the star to the outer limits of the disk as determined by the total integration time. Such observations will help to characterize the chemical and physical properties of the disk particles as a function of their distance from the star. By moving the star close to the edge of the coronagraphic hole, the disk is be probed as close as 2 AU from the star.

Near-IR Photometry of Candidate Companion to Proxima Centauri, Co-Investigator/GO (7847): A putative low luminosity companion to the closest star to the Sun, Proxima Centauri (dist. ~ 1.3 pc) has been identified. The candidate companion was discovered during Cycle 6 using the FOS as a coronagraphic camera (Program ID: 6059). The candidate companion is within ~ 0.4" of Proximal Cen, too close to be detected with WFPC2. It's apparent motion on the sky is similar to the parallactic motion of Proxima Cen, which makes its effect upon Proxima Cen difficult to detect with FGS astrometry. If the candidate companion is in orbit about Proxima Cen, modeling indicates the orbital period would be ~1 year. The ideal time to image the companion is during the latter half of the year (September-December) when it is farthest from Proxima Cen. HST NICMOS camera 1 observations are obtained to confirm/reject companionship, determine IR magnitudes, and to constrain orbital elements. Due to the small spatial separation and large magnitude differences, direct image detection of the companion cannot be done from the ground.

(Spectrophotometry and) High Resolution Imaging of HD 98800, Co-I/GTO (7232): HD98800, located nearby at a probable distance of 20 pc, is a unique stellar system consisting of two K7-V stars separated by 0.8 arcsec. Composite optical spectra show Lithium absorption, indicating pre-main sequence age, and IRAS found extraordinarily large amounts 165 K dust emission, suggesting the presence of a possible “zodiacal dust cloud in the making”. NICMOS Camera 1 was be used in five bands from 0.9 to 2.0 mm to make fully saturated MULTIACCUM images that can be deconvolved to separate the two well resolved bright stars from light scattered by the dust. If the dust cloud is sustained by a recently "failed planet" it should also be resolved at about 0.2" diameter. Comparisons of dust properties such as (a) scattered to emitted light, (b) color of scattered light and (c) size of the dust cloud can then be made with corresponding data for the solar system. Repeated observations enabled the dynamics of the systems to be established.

Spectrophotometry and Imaging of Pluto and Charon, Co-Investigator/GTO (7223): Detailed spectra of the individual members of the Pluto-Charon system were obtained. The conjecture of differing surface compositions, suggested by evidence obtained when the two were undergoing mutual eclipses were explored via grism spectrophotometry. These observations provided a direct comparison of the surface materials of each member of the double planet at their leading and trailing edges. Dispersed spectra were obtained at four separate orbital positions to to differentiate surface variations on the two objects. Charon's leading (in Charon's orbital direction) trailing, Pluto-facing and non-Pluto-facing hemispheres were observed.

A Search for Stellar Duplicity and Variability form FGS Guide Star Acquisition and Guiding Data, PI/AR (5811): The HST Fine Guidance Sensors (FGS) have the unique astrometric capabilities of revealing faint companions in close binary systems. They can measure their position angles and component separations, with a precision which exceeds that which is possible using any ground based techniques for primary components in the magnitude range V = 9 to 14. In addition, the intensity data, which are produced by the FGS PMTs, provide high precision relative photometry on rapid time scales. In mid Cycle 4 a new telemetry format was adopted for all normal operations which serendipitously provide these astrometric and photometric data at 40 Hz for all guide star acquisitions and periods of active guiding. This program is conducting a systematic examination of these data, obtained from the HST engineering telemetry, to perform a search for stellar duplicity to determine the incidence of doubles in the Guide Star Catalog as well as the separations, position angles, and relative brightnesses of the individual stellar components in such binaries. The light curves and power spectra of the photometric data are also being reduced and analyzed in an effort to perform an astroseismological survey of these stars, as well as look for and characterize variations due to other intrinsic mechanisms.

Duplicity and Variability in HST Guide Stars - An FGS Serendipitous Survey, PI/AR (8370) - A continuation of 5811. N.B.: Data resulting from all 40, 258 observations analyzed in this program have been ingested into the SIMBAD database.

High Spatial Resolution Imaging of Comet Hale-Bopp (C/1995 O1), Co-Investigator/GTO (7240): Comet Hale-Bopp provided an excellent opportunity for high-resolution imaging of the nuclear and inner coma regions of a bright comet. Observations in the near-infrared offered high contrast between the coma and nucleus since reflected sunlight/fluorescence are at a minimum and thermal emission from coma dust is important only at longer wavelengths. The primary scientific objectives were to probe the production of gas and dust in the inner coma very near the nucleus and to monitor the emergence and activity of jet structures. Images were obtained in/out of known spectral features due to water ice (2.04 mm), gaseous water (1.9 mm), and C2 (1.9 ? 2.0 mm). With a nuclear rotation period determined prior to the time of the observations, this will be used to devise an optimal strategy for measuring the nuclear brightness as a function of rotational phase. There also existed the possibility of nuclear fragmentation or flaring and indeed spiral jetting was seen. Observations were obtained as soon as possible after the comet emerged from solar avoidance and coordinated with contemporaneous imaging in the UV with the Space Telescope Imaging Spectrograph.

Pyramid Imaging of Circumstellar Material About Nearby Stars, Co-I/GO (6469): Observations obtained with the Infrared Astronomical Satellite (IRAS) have indicated that many of the nearby, bright stars have an infrared excess from a comparable sample of stars of similar spectral types. This IR excess has been attributed to emission from heated dust. Despite the definite presence of circumstellar dust for approximately one third of the nearby A-F stars, attempts at imaging candidates (other than Beta Pictoris) have yielded null results. Failure to detect these disks likely stemmed from the extreme differences in surface brightness between the central star and any surrounding disk material, as well as the evolution of such disks over time. The WFPC-2 pyramid edge will be used in a psuedo-coronagraphic manner in an attempt to detect and characterize circumstellar material about seven nearby stars which may have b Pic like disks as inferred from their IR excesses. Theories of planet formation based on nebular cosmogonies postulate that planets form during the contraction of a rotating gas cloud. Accretion of dust particles and volatile ices form planetesimals, the larger of which sweep up material from the nebula and grow into proto-planets. If disks are normal by-products during contraction of a nebular cloud and are common place, then what are their compositions, grain size, and how do they evolve with time? If disks exist about other stars, where are they? One would expect the inner regions of a disk close to the central star to experience rapid evolution through sublimation of ices and clearing of the disk through collisions with bigger bodies or particles falling into the central star, while the evolution of the outer disk regions will proceed at a much slower rate. The scenario involving infall and evaporation of comet-like bodies has been used to explain the presence of circumstellar dust about Beta Pic. If this model for processing of the disk material is valid, this process could be expected to occur about other stars, and in turn could explain the reported large IR excesses for many of the nearby stars.

Direct Imaging of the Circumstellar Disk of [[beta]] Pictoris, Co-Investigator/GO (6058): The unique imaging capabilities of WFPC2 onboard HST has been used to obtain high contrast, high resolution images of the dust disk (V = 16 mag/arcsec2) about b Pictoris (V = 3.9). With these, more accurate photometry of the disk may be obtained, the reported morphology (gaps) and variable disk thickness may be investigated along with the optical properties and size distribution of the circumstellar dust in detail. The b Pic circumstellar disk currently represents the best candidate for an extrasolar proto-planetary system or possibly a massive Kuiper belt. It is the only circumstellar disk that has been detected with ground-based coronagraphy. Accurate photometry is essential to determine the properties of the disk. Smith and Terrile reported an r-4.3 power law for the light distribution within the disk, while Artymowicz, Burrows, and Paresce reported a slightly less steep distribution of r-3.6. Their disk model suggested an upper limit for the tilt between the plane of the disk and the line of sight of 14°, with a mixture of grain sizes (radii between 1 and 20 mm) to explain the light scattering in the visible and IR images. Telesco et al. suggest the inner disk extends 50 AU (3 arcsec) from b Pictoris based on 10 and 20 mm observations, while Backman, Gillett, and Witteborn suggest the disk reaches inward to between 1 and 30 AU from IRTF observations. R-band images obtained with the Johns Hopkins University Adaptive Optics Coronagraph indicate an inverted asymmetry in the light distribution within 100 AU and imply a change in the scattering properties of the grains or a lower grain density in this region of the disk. There are possibly three processes involved in moving grains about in the disk: radiation pressure blowing small grains away from the vicinity of b Pictoris, Poynting-Roberston drag causing small grains to spiral into b Pictoris, and hidden planetary bodies perturbing the dust disk. Backman and Paresce suggest that planetary-like bodies orbiting at the inner boundaries of infrared-emitting regions could explain the central voids in circumstellar disks, while the outer disk could represent a Kuiper belt, a remnant of planetary formation. This program will shed some light on whether this model is correct are will help to answer the question "Do disks represent success or failure modes in planet building?''

HST/NICMOS Early Release Observation Programs

See Publication List for: NGC 2264 IRS [ref 10R], Orion 114-426 Silhouette Disk, [ref 11R], Nuclei of ARP 220, [ref 12R] Nucleus of IC 5063, [ref 13R], OMC-1, [ref 14R], and CRL 2688, [ref 15R].

HST/NICMOS Instrument Calibration and Engineering Programs

<>SMOV4 (CYCLE 17:)
NICMOS DC Transfer Function Test, Principal Investigator, 11406
NICMOS Filter Wheel Test, co-Investigator, 11407
NICMOS Focus and PAM Grid Tilt Tests, 11408
NICMOS Mode-2 Target Acquisition Test, Principal Investigator, 11413
NICMOS Coronagraphic Focus Determination, Principal Investigator, <>11414
NICMOS Coronagraphic Performance Assessment, Principal Investigator, 11415

<>Enabling Coronagraphic Polarimetry with NICMOS, co-Investigator, 9768
NICMOS Coronagraphic Performance Assessment 2, Principal Investigator, 9693

NICMOS Filter Wheel/Mechanisms Functional Test, Principal Investigator, 8944
NICMOS SMOV3B Transfer Function Verification Test, Principal Investigator, 8976
NICMOS Optimum Coronagraphic Focus Determination, Principal Investigator, 8979
NICMOS Mode-2 Target Acquisition Test, Principal Investigator, 8983
NICMOS Coronagraphic Performance Assessment - 1, Principal Investigator, 8984
NICMOS Coronagraphic Performance Assessment - 2, Principal Investigator, 9693

NICMOS Internal Parallel (Electrical Cross Talk) Test, Principal Investigator, 7032 & 7136
NICMOS Transfer Function Verification Test, Principal Investigator, 7037
NICMOS Target Acquisition Test, Principal Investigator, 7038
NICMOS Coarse Optical Alignment, Principal Investigator, 7041 & 7150
NICMOS Fine Optical Alignment, Principal Investigator, 7042
NICMOS Focus Monitor, Principal Investigator, 7043
NICMOS Coronagraphic Performance Verification, Principal Investigator, 7052
NICMOS Pre-Alignment Check-out, Principal Investigator, 7134
NICMOS Intermediate Focus/Alignment, Principal Investigator, 7135
NICMOS Coronagraphic Hole Monitor, Principal Investigator, 7154
NICMOS Revised Field Offset Mechanism Test, Principal Investigator, 7156
NICMOS Optimum Coronagraphic Focus Determination, Principal Investigator, 7157
NICMOS Coronagraphic Hole Location Test, Principal Investigator, 7808 & 7924

N.B. See separate Publication List for results from the above  Science and Instrument Calibration Programs.

Other Research Activities

TRACE/Inner Planetary Transits. Historically, the visual manifestation of the “Black Drop effect,” the appearance of a band linking the solar limb to the disk of a transiting planet near the point of internal tangency, had limited the accuracy of the determination of the Astronomical Unit and the scale of the solar system in the 18th and 19th centuries. This problem was misunderstood in the case of Venus during its rare transits due the presence of its atmosphere. Observations of the 15 November 1999 transit of Mercury were obtained, without the degrading effects of the Earth’s atmosphere, with the Transition Region and Coronal Explorer spacecraft. In spite of the telescope's location beyond the Earth's atmosphere, and the absence of a significant Mercurian atmosphere, a faint Black Drop effect was detected. After calibration and removal of, or compensation for, both internal and external systematic effects, the only radially directed brightness anisotropies found resulted from the convolution of the instrumental point-spread function with the solar limb-darkened, back-lit, illumination function. These effects were elaborated upon in light of earlier ground-based observations of transits of Mercury and of Venus (also including the effects of atmospheric “seeing”) to explain the historical basis for the Black Drop effect. The methodologies developed for improving upon space-based transit imagery are applicable to ground-based (adaptive optics augmented) and space-based observations of the 8 June 2004 and 5-6 June 2012 transits of Venus, providing a path to achieving high-precision measurements at and near the instants of internal limb tangencies. (publications [ref]: DPS [56M], Icarus paper [40R], IAU Proc [33P])

Dissertation Research, Department of Astronomy, University of Florida. The observation and analysis of lunar occultations. A systematic program of fast photometric observations of lunar occultations was carried out to measure stellar diameters, obtain better astrometric positions of stars, search for previously unsuspected stellar duplicity and provide fundamental data for the determination of time based on corrections and checks to the lunar theory. Fast photometric data acquisition instrumentation was designed and developed to carry out a systematic study of selected stellar targets which were occulted by the moon. New numerical techniques for data reduction and analysis, including the introduction of probabilistic constraints into a non-linear least-squares differential-correction model fitting process, were investigated and implemented. Physical parameters (including diameters) for many stars and stellar systems were successfully determined. Chairman: Dr. John P. Oliver. (e.g., see: Ph. D. Thesis [3O] or Program Summary [8R])

Asteroidal Photometry. Initiated a collaborative program of multi-color asteroidal photometry and fast photometric observations of asteroidal occultations of stars to determine the size, shape and density of selected minor planets, and to search for asteroidal duplicity. Designed and constructed portable photoelectric photometers, electrometer amplifiers, time-code converters and digital data acquisition electronics for remote-site observations. Deployable field stations were used for independent observations, and in conjunction with observations made at Rosemary Hill Observatory (RHO) and other fixed observatory sites. Profiles, diameters, and densities, as well as other physical and photometric properties of many asteroids were determined, including Nemausa, Pallas, and Ceres. This program was conducted under a grant from the University of Florida's Division of Sponsored Research. (e.g., : [51] Nemausa [3R] Ceres, [4R], and Pallas [7R])

Numerical Modeling of White Dwarf Stars. Developed a computational model for investigating dynamical instabilities in the structure of white dwarf stars of varying chemical compositions, ionic partitions and central densities, applicable over a wide range of partial and total degeneracy regimes. The model included such affects as Coulomb interactions between electrons and nucleons, inverse beta decays, the effects of the general theory of relativity on the condition on hydrostatic equilibrium (local and global), stellar rotation, mass accretion in binary systems and interactions with external magnetic fields. This work was supported by a grant from Warner Computer Systems, Inc. (e.g., see: "Astrophysical APL - Diamonds in the Sky" [2P])

Polar Atmospheric / Climatological Research. The integrity of the synoptic meteorological record of the South Pole is important both to the continuing effort to understand the climatology of the Antarctic Plateau, and to a number of interdisciplinary studies aimed at discovering the details of the mechanism responsible for the depletion of upper atmospheric ozone. An analysis of the nighttime synoptic meteorological record from the South Pole station was undertaken, and a systematic error in the sky cover observations was discovered. As a result it was determined that the seasonal variations in sky cover, as inferred from these observations, are not nearly as significant as previously believed. This project was partially supported under National Science Foundation grant DPP 86-14550.

N. B.: See Publication List for cited references (indicated [##]).

Total Solar Eclipses

Dr. Schneider is a member of the International Astronomical Union’s Working Group on Solar Eclipses. He is recognized as a leading expert in the high-precision numerical calculation of eclipse circumstances and the application of those computations in planning and carrying out observations of total solar eclipses. For more than three decades, Dr. Schneider has lead expeditionary groups and conducted such observations on land, sea and air of twenty-three (of the twenty-four) total solar eclipses occurring since 7 March 1970 from remote locations across the globe conducting direct, polarimetric, and spectrophotometric imaging programs. Additionally, He has executed two, and planned five, high-altitude eclipse intercepts with jet aircraft:

•Planned and Executed: A 44,000 ft very highly technically challenging and navigationally critical intercept using a Citation II over the North Atlantic on 03 October 1986.

•Planned and Executed: A 41,000 ft intercept over the South Atlantic, working in situ on the flight deck of a VASP airlines DC-10, extending the duration of totality to 6m 15s.

•Planned: A supersonic one-hour totality at 60,000 ft intercept over the South Atlantic using an Air France Concorde. Very sadly, this was cancelled due to the grounding of the Concorde fleet following the horrific crash of AF 4590 outside of Paris on 25 July 2000. and

 •Planned and Executed: The QANTAS 2901 / 23 November 2003 Antarctic eclipse flight.

•Planned and Executed: The Lan Chile 8001 / 23 November 2003 Antarctic eclipse flight.

The planning of the above airborne observations was rooted in the use of the EFLIGHT S/W, created by Dr. Schneider, specifically to address the problem and optimization of intercepting the moon's shadow from a moving aircraft. The core algorithms were developed for the highly technically challenging 1986 eclipse intercept and were augmented for the 1992 eclipse flight to provide greater flexibility for real-time use on the DC-10 flight deck. The S/W was modified in preparation for the 2001 Concorde eclipse flight, for consideration of an intercept in the supersonic regime where the instantaneous speed of the aircraft was greater than that of the lunar umbra given the geometrical circumstances of that eclipse. Most recently EFLIGHT was again modified specifically for the “over the pole” approach geometry of the lunar shadow for the 23 Nov 2003 eclipse and tailored for real-time use given the manual input requirements of the Boeing 747-400 FMS, to enable an observational program in co-ordination with contemporaneous observations of the LASCO/C2 coronagraph on the SOHO spacecraft.

Previous Employment/Positions

Computer Sciences Corporation - Space Telescope Science Institute (1985-1994)

Appointment/Functional Responsibility: Served for nine years as an Operations Astronomer in the Operations, and Science and Engineering Support Divisions at STScI.

General Responsibilities: Appointed as a member of the Instruction Management (Science Instrument Commanding) Task Group. Designed, implemented, and tested science commanding instructions (for the Science Planning and Scheduling System (SPSS) /Science Commanding Subsystem of the Hubble Space Telescope Science Operations Ground System (SOGS)). Developed operational procedures, science instrument command groups and supportive file structures for inclusion in the HST Project Data Base (PDB) for operating the Wide Field/Planetary Camera (WFPC), Fine Guidance Sensors (for astrometric science), Wide Field/Planetary Camera-2 (WFPC-2), as well as other Science Instruments and spacecraft subsystems. Participated in the validation of low-level and atomic command constructs tested during Assembly and Verification for all HST Science Instruments. Adapted these for use in the SOGS and Payload Operations Control Center/Applications Support Software (PASS) ground systems. Designed and built higher-level logic to control the use of these command structures. Developed requirements and software interfaces for driving flow-down control logic from a structured Proposal Management Data Base (PMDB) and calendars of time-ordered events. Developed and implemented reconfiguration instructions and associated table driven logic to allow for automatic setup and transitioning of the science instruments to/from various defined operational states. Generated detailed requirements for the proposal Transformation software. Contributed to the Proposal Instructions and Instrument Handbooks.

WFPC-2: In preparation for the on-orbit installation of WFPC-2 was responsible for working with the WFPC-2 Science, Instrument Development, and Integration & Test teams in both pre-launch testing of the hardware and ground system software. This effort engendered gaining specific first-hand knowledge of the workings of the instrument by participating a series of ground system, thermal vacuum, hardware, and system functional tests. This also encompassed participation in the SMOV Proposal Implementation Team. Assisted in defining the overall implementation requirements for WFPC-2 SMOV and performed detailed reviews of those proposals, implementation plans, calendars and SMSs. Supported the HST servicing mission by first participating in a number of pre-launch simulation and training exercises, and later performing real-time monitoring, data collection and evaluation during the servicing mission itself.

* Command Development: Developed ground system command constructs which were required for testing and operating the WFPC-2, both pre-launch and on-orbit. The scope of this activity was sufficiently broad so involvement went beyond just creating executable procedures and software, but lent itself to active participation in and contributing to development efforts across many groups at STScI, MOSES, JPL and the WFPC-2 Science team. The need to be responsive to ever changing demands and requirements were met as the operational methodologies and instrument characteristics evolved and/or solidified during the long series of ground tests which occurred during this period.

* SLTV: Actively participated in the WFPC-2 System Level Thermal Vacuum Test and Instrument Calibration as the STScI/Science Commanding on-site representative at JPL. Worked closely during round-the-clock shifts with JPL hardware, S/W, instrument and science team personnel. Defined, modified, executed and analyzed real-time tests designed to explore and evaluate the operating characteristics of the WFPC-2. Investigated anomalous behaviors which led to both a better understanding of the instrument, and to changes in the methods of operating and commanding it. Information and knowledge that was acquired during SLTV was transferred to other STScI and WFPC-2 project personnel and incorporated in the implementation of the WFPC-2 stored command instructions. Worked with the ESB WFPC-2 engineer on obtaining the SLTV engineering data in a timely manner from JPL and porting it to a data archive at STScI.

* Tests and Simulations: The exercise of pre-deployment validation of a new science instrument required extensive sub-system and integrated tests to be run both ground and flight hardware and software. Supported this effort by contributing to, and participating in the various ground system and functional tests, discrete simulations, and joint integrated simulations. In particular, to validate the command generation capability of the ground system for the WFPC-2, and the response to those command requests by the instrument created test proposals, calendars, and SMS's used in these series of tests. Worked with the MOSES SI personnel in reviewing new Real-Time command procedures that were needed in support of these tests, and the servicing mission. Monitored the ground system and instrument behavior during execution, and participated in real-time hardware and software anomaly analysis and resolution. Worked with other members of flight team, through the real-time simulations, to define and improve procedures to be used during the servicing mission.

* Servicing Mission: Assisted in preparing and configuring the ESB/commanding work site at the OSS facility by setting up the hardware and S/W interfaces to permit real-time analysis on the engineering data. Developed adjunct data collection and analysis tools, and set up automated data reduction and network transfer processes. During the Servicing mission participated in the 24-hour commanding shift coverage - monitoring instrument and spacecraft sub-system changeouts. Key subsystem parameters were watched and trended and, for the WFPC-1 and 2 in particular, thermal considerations were constantly addressed and discussed with other project elements - as were contaminant and other issues of real-time concern.

* Serving Mission Observatory Verification: Served as a member of the SMOV Proposal Implementation Team. Worked on the development and implementation of engineering, calibration, and ERO proposals for the SMOV program in consultation and association with the WFPC-2 IDT and I&T teams. Identified the need for special commanding and/or structuring of the PMDB through a series of proposal implementation meetings and reviews. Built, tested, and delivered non-standard commanding for early operations of the WFPC-2. Test, and later flight, calendars and SMS's were microscopically reviewed for any deficiencies - and proposals reworked as needed when problems were found. During execution monitored all first-time operations, and was prepared to responded to unanticipated anomalies. Throughout this era worked with the WFPC-2 engineering and science teams (JPL and SIB) to evaluate the instrument's performance and provided information on commanding related activities to these groups through regular calibration and team meetings. Worked with the with the WFPC-2 science team to develop a coherent transition plan to the Cycle 4 calibration program. Currently working with both the IDT and STScI/SIB on defining additional on-orbit and laboratory tests to better characterize and calibrate the photometric performance of the instrument, based upon on-orbit data.

WFPC-1: Participated in the planning and implementation of all ground system simulation, throughput, and vehicle tests. Prepared special commanding instructions and structured inputs for the WFPC-1. Worked on the production, and reviewed the content, of the WFPC-1 commanding on Calendars, Science Mission Specifications (SMS's) and command loads used in all Ground System Tests (GST's). Supported real-time monitoring of the use of the WFPC-1 during integrated system GST's. Participated in the development and implementation of many special WFPC engineering operations, procedures, and instructions including the implementation and redefinition of the UV Flood, CCD decontamination procedures, integration of the NASA Standard Spacecraft Computer-1 (NSSC-1) soft safing capability and Real Time safing recovery plans. Worked with GSFC Flight Software Group (Code 512) in defining special executive flight software requirements, and WFPC/NSSC-1 command interfaces for special operations. Provided "emergency" support for unplanned safing events, WFPC instrument anomalies and unforeseen Target of Opportunity observations. Worked with WFPC engineers (both contractor and in-house) and representatives of the Telescope Instrument Branch in assessing general post-launch instrument performance, operational use trending, and in response to directed technical inquiries. Worked with the WFPC on-site Instrument Development Team (IDT) representative to help assure that new WFPC command capabilities (not originally specified by the IDT) were implemented and assimilated into the ground systems in a faithful and efficient manner. Created new instructions, data base definitions, and supported ground testing and validation of these capabilities, which included: the on-board WFPC Idle checking (and bay 5 temperature regulation) software; suppression of CCD erasure following preflashes; issuance of autoerase commands following pyramid rotations; allowing Kspot, Bias, Dark and exposures to be preflashed and CR-Splitting of the latter two; and permitting subsetted CCD reads with efficient use of the onboard tape recorder and/or communications downlink.

Observatory Verification: Member of the Orbital Verification (OV) Planning/Implementation Team. Reviewed and identified technical problems in OV proposals. Developed solutions to these problems and worked with the IDTs to reach closure on those items. Wrote detailed implementation plans used by personnel involved in defining science and engineering objectives, planning and scheduling of activities, developing, testing, and implementing special science instrument and spacecraft subsystem commanding, identifying required real-time support, and supplying specific database constructs and entries needed to carry out these proposals.

FGS/Astrometry: Served, for two years, as the STScI Operation Division's technical representative to the Space Telescope Astrometry Team. Worked with the team on defining baseline functional astrometric requirements. Developed command constructs and procedural logic for using the HST Fine Guidance Sensors (FGS's) to carry out astrometric science observations, and special Orbital Verification focus and alignment tests. Oversaw the creation of test calendars, and SMS's used to validate FGS commanding. Participated in ground-system simulation, unit level hardware, and vehicle testing of Fine Guidance Electroncs/FGS commanding. Developed and provided software to assist in the Real-Time analysis of FGS, Pointing Control System and Optical Telescope Assembly telemetry during early on-orbit operations.

Operations Support: Reviewed proposals scheduled for execution and resulting commanding on flight SMS's. Participated in iterative SMS analysis/rerun cycling during the OV, SMOV, Science Verification epochs, and Science Assessment and Early Return Observations. Uncovered and reported numerous problems, developed and offered solutions to SPSS, User Support and Science Planning Branches (SPB) as appropriate. Worked with SPSS personnel on fixing many problems related to improper PMDB population or proposal structure, and interpreting PASS mission scheduler and command loader products. Often consulted with the proposer (directly or through SPB) to recommend proposal changes to enable his/her scientific or engineering goals to be accomplished when the proposal itself was improperly or incompletely specified. Developed many software tools which were provided to various branches of the Operations and Systems Engineering divisions to assist in validating the integrity of transformation products, the PMDB, and flight SMS's and to facilitate engineering data analysis.

HST/WFPC (1 & 2) Instrument Calibration & Engineering Programs:

WFPC-2 SOFA Partial Stepping Test, Co-Investigator
WFPC K-Spot Reflectivity Test, Principle Investigator
WFPC Calibration: UV-Flood Test, Co-Investigator
WFPC Calibration: UV Grism Test, Co-Investigator
WFPC Light-Pipe Throughput Test, Co-Investigator

Department of Astronomy - University of Florida (1978-1982, 1984-1985)

South Pole Telescope: Designed, implemented and tested the firmware program for the automated operation of the University of Florida's multi-color photometric South Pole Telescope. Developed process control, data acquisition and calibration management software. Assisted in telescope, photometer, and control system mechanical and electronic design, fabrication, and telescope calibration. Performed instrument installation, photometric calibration and operational field check at the Amundsen-Scott South Pole Station. Performed instrument anomaly analysis during observing season. Returned to the South Pole for post-season instrument performance evaluation and engineering diagnostics. Reduced and analyzed photometric data as part of a quantitative site survey program, as well as astronomical studies of g2 Velorum and HR 2554. This work was supported by National Science Foundation grants DPP 82-17830 and DPP 84-14128.

Additional Instrumental Work: Designed, fabricated, and installed a new Cassagrain light baffle and offset guiding systems for the RHO 76 cm. telescope. Designed and built a multi-channel digital data acquisition system to be used by several photometric instruments. Redesigned and put into working service a 3-color flare star photometer. Designed and constructed coelostat fed flash spectrograph employing a U.T.-synchronous high speed camera used for obtaining time resolved spectra of the solar chromosphere and inner corona during the inner tangential contacts of solar eclipses. Interfaced an Ebert-Faste scanning spectrograph to a microprocessor based control system, and used this system to determine the size of the Ha emission region of several B-emission (shell) stars, including Zeta Tauri. Performed maintenance and repairs on Alvin Clark 20 cm. refractor and Celestron telescopes at UF's student observatory.

Space Astronomy Laboratory - University of Florida (1982-1984)

Giotto/Halley Optical Probe Experiment: Ground System data acquisition and real-time analysis S/W lead for (multi-channel photo-polarimeter employing a MAMA detector) flown on the European Space Agency's Giotto Mission to Halley's Comet. Designed, developed and programmed ground support equipment and real-time spacecraft simulator. Assisted in optical calibration, electronic circuit board design, fabrication, and calibration of engineering and flight model units. Performed flight unit engineering checkout during spacecraft/payload Assembly & Verification at British Aerospace. Worked with project mission planners and scientists at the European Space Agency (Noordwijc, Netherlands) and Service d'Aeronomie-Centre National de la Recherche Scientifique (Paris, France) on many payload interface and operational issues.

Additional Instrumental Work: Specified, designed, and programmed a microcomputer interface for an optical vignetting table for photometric and radiometric calibration of spacecraft instrumentation as part of a collaborative project between the Space Astronomy Laboratory and Ruhr-Universitat, Bereich Extraterrestrische Physik (Bochum, W. Germany).

Warner Computer Systems, Inc. (1976-1980)

APL Technical Consultant: Maintained public and development system workspace libraries. Wrote system specific application functions and integrated them into the libraries. Developed plotting/graphics display software for Tektronix, Versatek, and Diablo/Spintronic devices. Supervised creation of documentation of APL software libraries by technical writing staff.

APL Technical Analyst: Developed turn-key end-user directed software systems. Products created included software for econometrics forecasting, statistical analysis, laser/resonant-cavity design, message and packet switching, and inventory and process control. Conducted APL programming classes and handled technical inquires from time-sharing clients.

Teaching Experience

Taught laboratory and lecture sections of introductory/general astronomy, astronomical techniques, and digital electronics. Planned, supervised and evaluated exercises in astronomy, data manipulation and analysis, instrumentation, and photographic and photoelectric photometry. Taught seminar series on APL  programming for physical sciences and computer programming with APL.

Observing Experience

Hubble Space Telescope:
  Near Infrared Camera & Multi-Object Spectrometer
  Wide Field/Planetary Cameras (1 & 2)
  Fine Guidance Sensors (astrometric interferometry)
  Space Telescope Imaging Spectrograph

Transition Region Coronal Explorer (TRACE)

Heinrick Hertz Sub-Millimeter Telescope

Palomar/PHARO Adaptive Optics System


Bok 2.3 meter Telescope

Data Analysis/Reduction from Keck-II and Lick {NGS+LGS} AO Systems and IRTF

Solar chromospheric/inner coronal spectroscopy and polarimetry

76, 45, and 40 cm. reflecting telescopes

A wide range of small fixed, and portable optical telescopes

Multi-color differential photometry of eclipsing and intrinsic variables

Fast photometry of lunar and asteroidal occultations

Photography with hyersensitized plates

Plate reduction with iris photometer and microdensitometer

Computer Experience

Hardware, Mainframes/WorkStationsOperating Systems: VAX 11/750,11/780, 8600, 8800, Alphas (VMS); Sun SparcStations (Solaris 2.4); Apple Macintosh G4, G5, Intel (MacOS X); Xerox 6/7/9 and 560 systems (CP-V, UTS, BPM); IBM 360, 370, 3033N, 3081, 3094 and 4341 (OS/VS, MVS); DEC 20 (TOPS); Ahmdal 470/V6; Harris 500; PDP-11/34; Data General Nova

Hardware, Micros/PC's: Rockwell AIM-65 and RM-65 systems; Apple Macintosh 68K-G3 (MacOS, all flavors 6.0-10.2.6); Apple II, II+, IIe; HP-85a; MCM 700; Commodore Pet, SX-64, and SP-9000; IBM 5100, 5110, and Pc

Software: APL, IDL, FORTH, BASIC, 6502, 6800 and RCA 1802 machine and assembly languages.  Special Purpose Application Programs: numerous for data analysis packages, graphics and image display (e.g., TRANSFORM, KALEIDAGRAPH, PHOTOSHOP, CANVAS) Systems utility functions and development s S/W: MacOS and VMS.

Professional Society Membership

International Astronomical Union (division DII working group on solar eclipses 2003-2006)

American Astronomical Society

SPIE (International Society for Optical Engineering)

American Association for the Advancement of Science

Association for Computing Machinery (SIGAPL)

International Occultation Timers Association

Honors and Awards

ASTRONOMICAL SOCIETY OF THE PACIFIC - Maria and Eric Muhlmann Award for 2003 (NICMOS IDT)

NASA/GSFC - Science Leadership Group


NASA - Public Service Achievement Award (HST Orbital Verification)

NASA - Achievement Award (WFPC-2 Science Team)

NASA - Project Award (HST Program)

NASA - Project Award (HST 1st Servicing Mission)

JET PROPULSION LABORATORY - Wide Field/Planetary Camera II Project Award (SLTV and Calibration)

NASA/GSFC - Achievement Award (HST 1st Servicing Mission WFPC-2 Development and Delivery)

NASA/GSFC - Achievement Award (HST 1st Servicing Mission Integration & Test)

NASA/GSFC - Achievement Award (HST 1st Servicing Mission Observatory Verification)

NASA/GSFC - Achievement Award (HST NSSC-1 FSW, Mission Ops, Engineering Support, IDT)

NASA/GSFC - "Special Act" Award (HST Continuous Process Improvement Team)

NASA/GSFC - Certificate of Recognition (HST Program)

NYIT - Physics Research Award

NYIT - Silver Medal for Physics Research

Member: Sigma Pi Sigma (National Physics Honor Society)

Recent Public/Community Service

Hubble Space Telescope Post-SM4 Scientific Review Panel (D. Black, Chair)

Independent Report to STScI: HST/NICMOS & Ground-based/AO Capabilities

(NASA/GSFC) NICMOS Dewar Anomaly Review Board (G. Morrow, Chair)


See separate publication for:
• Refereed Publications (48)
• Conference Proceedings (39)
• Meeting Abstracts/Presentations (89)
• Selected Solicited NASA/STScI Reports (9)
• Poster Displays/Presentations (38)
• Recent Invited Talks (Symposia, Colloquia, etc.) (7)
• Others (5)

Available as an HTML (web-based) document with embedded URL links to cited publications at

Additional information: