11 JULY 2010 TOTAL SOLAR ECLIPSE

GROUND-BASED EXPEDITION TO HAO ISLAND ATOLL, FRENCH POLYNESIA

PLUS LIMITED-AVAILABILITY OPTIONAL ADD-ON
> 9 MINUTE DURATION TOTALITY HAO-LAUNCH & RETURN ECLIPSE FLIGHT
 
ORIGINATING FROM AND RETURNING TO LOS ANGELES, CALIFORNIA USA

Glenn Schneider, Steward Observatory, University of Arizona
Phone: 520-621-5865, email: gschneider@mac.com

Total solar eclipses (TSEs) are one of nature's most dramatic and awesome spectacles - but often occur in remote locations posing logistical (and financial) barriers to accessibility.  The most recent TSE, on 22 July 2009, was visible from highly populated areas in India and China, and provided the opportunity for those who ventured to the point of maximum eclipse in the Pacific Ocean (e.g., on the Costa Classica cruise organized by Roy Mayhugh and "Astronomy Vacations") to view the longest land- or sea-based total solar eclipse for more than a century to come. But, many were then left wondering "what about the NEXT one?"  The path of totality for the 11 July 2010 solar eclipse soon to be upon us, traverses a vast, but narrow, stretch across the south Pacific Ocean (see map below) — with landfall opportunities few and far between on only a very small number of sparsely populated islands.  Just moments before sunset umbral landfall occurs in Patagonia, but eclipse visibility will be problematic in the limited locations there where the path can be accessed both because the local climate presents a very high likelihood of cloud cover and mountains to the west will block many lines-of-sight to the horizon-hugging setting Sun.


The total phase of the 11 July 2010 solar eclipse will be visible only from within the "path of totality" — the narrow arc-like strip on the map above — centered on the southern Pacific Ocean.
(Map source: NASA TP/2008-213171 by Espenak and Anderson)

Most of the few small Pacific islands that will be immersed in the moon's umbral shadow are difficult to access and lack infrastructures capable of supporting anything but, at best, very small numbers of eclipse chasers.  For years (if not decades), Easter Island, Chile, within the eastern part of the path of totality, has drawn the attention of eclipse chasers in anticipation of TSE 2010 because it does routinely entertain tourist visits both by commercial air and visiting cruise ships, but only in very limited numbers.  While some eclipse chasers will be headed that way, Easter Island is quickly reaching its capacity for hosting eclipse observers. Moreover, it is in the comparatively drier portion of the track passing through French Polynesia where eclipse-obscuring clouds are less likely than points further east (i.e., Easter island and Patagonia), or further west (i.e., Cook Islands).

Small aircraft can provide transport to a few small in-totality islands in French Polynesia, but only in very limited numbers.  The solitary exception is the often overlooked Hao Island Atoll, about 920 km (497 nautical miles) east of Tahiti — quite off the beaten path of "normal" island tourism in French Polynesia.  Hao Island has a population of appx 1,200 in a single village on its northeast side named Otepa primarily sustained by pearl harvesting. 


A view of the Hao Island marina at the village of Otepa.

Other than Easter Island (Chile), Hao Island (French Polynesia) is the only island within the path of totality with an airport facility capable of accommodating a large commercial jet aircraft filled with eclipse chasers!

The Hao Island atoll quietly boasts an 11,089 foot x 148 foot (!) hard surface runway and airport complex — nestled between the surf-breaking shores of the Pacific Ocean and the island's interior lagoon where TSE 2010 will be observed right from the airport with a totality duration of 3m 37s and the Sun 33° above the horizon at mid-eclipse.

 HAO ISLAND, FRENCH POLYNESIA:

Hao Island as seen from above.  Left panel: The northeast side of the island showing the 11,089 foot (3,380 meter) runway.  The airport complex is to the northwest, and the village of Otepa is to the southeast, of the runway.  Inset: Hao as seen from the space shuttle (unrectified image, looking down at where they hoped not to land) from STS-100 on 28 April 2001.  Right: Rectified image of Hao Island, approximately 55 km from the NW to the SE ends.  Image sources: NASA and Google Maps.
CLICK on the above image to see at twice the resolution, or click HERE to explore the Hao Island airport with Google Maps.


Hao Island airport operations, aircraft service, and support facilities and structures.



Given its small population and geographically remote location, why does Hao Island have such a significant airport facility?  Historically, Hao Island was a logistical staging area for the now-terminated French nuclear testing program.  Subsequently, the air facility became designated as a space shuttle emergency landing facility (but, thankfully, has never had to be used for that purpose!).  More recently, Hao Island airport was turned over from military to civilian French Polynesian operating authority (click HERE for the current Air (Operations) Directive for Hao).  Today Air Tahiti — the regional carrier for French Polynesia, not to be confused with Air Tahiti Nui, the international carrier — operates a limited number of inter-island flights to and from Hao on smaller aircraft.  Although the Hao Island airport is capable of servicing large, long-range commercial jet aircraft,  there has never been any need for it to do so — until now.

Additionally, the Hao Island atoll serendipitously finds itself in a "sweet spot" in longitude along the path of totality — centrally within a climatological local minimum in mean cloud amount, making it the ideal place for eclipse chasers to deploy for TSE 2010.


 Comparison of historical July average cloud obscuration (weighted by sky coverage and frequency of occurrence) among ground-based, potentially accessible, observing locations. Climatology data adapted from Jay Anderson; see additional data for other longitudes and locations.


Comparison of July monthly mean cloud cover frequency (percentage of time) as a function of cloud obscuration, as compiled by Jay Anderson, for Hao Island and Easter Island.  Easter Island experiences heavy (median 75%) broken to fully overcast skies significantly more frequently than Hao Island. Conversely, and favorably, less-obscuring light (trace or scattered) cloud cover is more frequent on Hao Island than on Easter Island.


Because of the advent of the 11 July 2010 eclipse visible from the airport facility at Hao, and the likely highest ground-based probability of clear skies, we are arranging a charter flight of a large capacity long-range jet aircraft originating from and later returning to Los Angeles, California, USA to bring approximately 300 people to Hao directly from LAX to view TSE 2010.

Definitive departure and arrival times from (and back to) LAX are still TBD, but our charter flight will be scheduled to arrive on Hao at least three hours before eclipse first contact. The aircraft will remain on Hao until approximately 3 hours after fourth contact (so, bring a bathing suit for a post-eclipse celebratory swim!).  See the preliminary Hao Island schedule below.

PRELIMINARY HAO ISLAND SCHEDULE (subject to change and optimization)

 U.T.
 Local (UT - 10h)
 Alt°
 Az°
Hao Latest Aircraft Arrival
 14:25
 04:25

Hao, Sunrise
 15:59:40 05:59:40 0
 66.7
(Est. EFLIGHT Take-off)
 est 17:16
 est 07:16

Hao, 1st Contact
 17:24:39 07:24:39
 18.0
 58.6
Hao, 2nd Contact
 18:41:23 08:41:23
 32.6 47.4
Hao, Mid-Eclipse
 18:43:11 08:43:11
 32.9
 47.1
Hao, 3rd Contact
 18:45:00 08:45:00
 33.2
 46.7
Hao, 4th Contact
 20:12:57
 10:12:57
 45.8
 25.8
(Est. EFLIGHT Landing) est 21:38
 est 11:38

Hao, Earliest Aircraft Departure est 23:00
 est 13:00

Hao, Sunset (after departure)
 02:59:05 12 July
 16:59:05 11 July
 0
 293.2
Local eclipse circumstances for Hao Island airport (18° 04' 21.00" S, 140° 56' 53.94" W).  Totality duration = 3m 37s.
 

But wait... There's MORE!

After arriving on Hao, approximately 250 island-based observers will deplane and prepare to observe the eclipse. But, since the charter aircraft "is ours"...

We will then launch a mission-optimized "add-on" eclipse flight (EFLIGHT 2010) from Hao Island using the same aircraft to carry up to approximately 50 people to view totality from ~ 11 km (36,000 ft) above the surface of the Earth yielding a duration of totality of approximately 9m 13s!

Our baseline EFLIGHT 2010 flight scenario is illustrated above (click on the map to see it at a larger scale). After bidding a fond pre-eclipse farewell to our ground-based friends on Hao Island, EFLIGHT 2010 will launch from the Hao airport (1) at approximately 17:15 UT to rendevous with the moon's umbral shadow.  After traveling eastward for approximately two hours, at five minutes before second contact, the aircraft will execute a shallow right hand turn (2) turn to place it on a track (the totality run) so it will pass centrally through the umbra at mid-eclipse with the Sun "straight out" the left side windows.  (3) — At second contact (19:15:24 UT) the leading edge of the umbra will overtake the aircraft and a glorious diamond ring effect (see middle picture below from EFLIGHT 2008) will be prolonged by the aircraft's speed relative to the Moon's shadow.   (4) — At mid-eclipse (19:20 UT)  with the aircraft  on centerline and located centrally in the Moon's shadow, it will be most deeply immersed in the Moon's shadow giving spectacularly high contrast views of the solar corona from 36,000 feet.  (5) — It's over!  A parting third contact diamond ring, and a total solar eclipse for the record books with over 9 minutes of totality observed!  We then remain on the totality run track for another 2 – 3 minutes taking advantage of views to the horizon more than 350 km away at our altitude to watch the umbra in the sky above and projected on the ocean below whisk ts way toward southern South America before returning to space.  We then execute a right hand turn to begin our approximately two hour westward return flight back to Hao Island, to join in the post-eclipse celebration back on the ground.

Note: The number of EFLIGHT 2010 participants will be limited by the number of Sun-side (left side) windows on the aircraft to about 50 people.  From our flight altitude of approximately 36,000 feet our view of totality will be unaffected by cloud and local weather below. We currently are planning to target for a mid-eclipse central umbral-shadow intercept at 19:20 UT.

EFLIGHT 2010 — 11 JULY 2010 TOTAL SOLAR ECLIPSE AT 19:20 UT (Flight Level 36,000 ft.,  Ground Speed 490 nm/hr)

 U.T.
 Local (UT-10h)
 Alt° Az° Long.
 Lat.
 Dist (nm)
Est. Latest Wheels-Up Hao
 17:16
 07:16



0.0
EFLIGHT 2nd Contact
 19:15:24
 09:15:24
 45.8
 27.2
 126° 45' 36" W
 17° 55' 24" S
 811.2
EFLIGHT mid-Eclipse
 19:20:00
 09:20:00
 46.3 24.9
 126° 09' 52" W
 18° 11' 16" S
 37.5
EFLIGHT 3rd Contact
 19:24:37
 09:24:37
 46.7
 22.6
 125° 34' 00" W
 18° 27' 12" S
 37.6
Est. Wheels-Down Hao
 21:38
 11:38



*960.0
Notes:  1. Totality run to place the Sun "straight out" the main cabin windows at mid eclipse (heading 114.9°)
            2. Est. round trip distance Hao –> EFLIGHT 19:20 UT mid-eclipse –> Hao =  1,765 nm
            3. Est. round trip time (including takeoff, ascent, descent, landing) = 4h 22m
            4. * Includes additional 82 nm to extend totality run 3 minutes after 3rd contact (and return)       
   
This eclipse flight will result in the longest duration of totality ever observed with a non-experimental or non-military aircraft in history (a supersonic experimental Concorde flight in 1973 achieved an astounding 74 minutes in totality — a record that will continue to stand for quite some time).  This is more than two and a half minutes longer than seen on the Costa Classica from the point of maximum eclipse during the recent "big one" on 22 July 2009 (longest total solar eclipse from the ground for more than a century to come), and more than a minute and a half longer than celestial mechanics will ever allow for a ground-based observer.

The TSE 2010 eclipse flight launched from Hao Island will be conducted as an eclipse-optimized "EFLIGHT" under the technical direction of Dr. Glenn Schneider (Steward Observatory, University of Arizona) — following the precepts and procedures developed, tested, and validated on our previous TSE 2008, 2003, and 1992 EFLIGHTs — to provide the best views possible of the total phase of the eclipse.



Views of totality and the Moon's shadow on the Earth below and sky above from EFLIGHT 2008 flying (as also planned for EFLIGHT 2010) at 36,000 feet.

As with previous EFLIGHTs, we remain flexible to modify the flight plan in real-time, within aircraft operating parameters, in reaction to flight conditions on eclipse day to enable an eclipse-optimized "totality run".  The exact duration of totality will depend, in part, upon our air speed and the winds aloft. In baseline flight planning we assume a nominal ground speed of 490 nm/hr (907 km/hr), but within the anticipated variances a totality duration exceeding nine minutes is achievable.

EFLIGHT 2010 — ACHIEVABLE DURATION FOR A SUBSET OF ALTERNATE MID-ECLIPSE INTERCEPTS (FL360, no wind)
UT mid-eclipse
 Totality Duration
 Alt° Az° Long
 Lat.
19:10
 08m 35.4s
 44.3
 32.4
 129° 32' 06" W
 17° 27' 02" S
19:15
 08m 57.1s
 45.4
 28.7
 127° 49' 21" W
 17° 46' 48" S
19:20
 09m 13.2s
 46.3
 24.9
 126° 09' 52" W
 18° 11' 16" S
19:25
 09m 22.2s
 46.8
 21.0
 124° 32' 47" W
 18° 40' 16" S
19:30
 09m 23.7s
 47.1
 17.0
 122° 57' 22" W
 19° 13' 41" S

Mid-eclipse intercepts earlier in time than 19:20 UT would reduce the achievable duration of totality, and later times up to ~ 19:30 UT will increase the achievable duration of totality but with a diminishing time and cost vs. duration trade.  At this time, the 19:20 UT scenario is baselined.  Mid-Eclipse intercept points closer to Hao (earlier than 19:30 UT intercept) that would reduce EFLIGHT end-to-end times are being evaluated for execution on an as-needed contingency basis. 

To achieve an extraordinary and unprecedented duration of > 9 minutes of totality, the eclipse will be observed where the altitude of the Sun during totality will be approximately 45° above the astronomical horizon.  This relatively high solar altitude, "half way up" the sky, is still well suited for out-the-window eclipse viewing — but, for most people, would preclude two people seated in a window row from simultaneously sharing a window to view the eclipse, and could also pose some challenges for more sophisticated photographic programs.  For this reason EFLIGHT 2010 will be limited to only as many passengers as there are eclipse-side (left-side) accessible windows (appx 50, exact number TBD).  Specific exceptions for "time-sharing" partners may be accommodated, but the practical limitations on window sharing imposed by the altitude of the Sun must be understood by all EFLIGHT 2010 participants in advance.

Note that the EFLIGHT 2010 segment can additionally offer de facto "cloud insurance" for any Hao Island observers who also sign up for the EFLIGHT. Hao Island expedition participants who have signed up for the EFLIGHT 2010 add-on are empowered to make an in situ decision to either remain on Hao for the eclipse if they prefer, or take to the skies as insurance against the possibility of interference of eclipse-obscuring clouds on the ground.  Dedicated Hao Island only observers, however, will not have the option at the "last minute" (i.e., in situ) to join the EFLIGHT due to the limited number of pre-booked and assigned aircraft windows.

INTERESTED?  QUESTIONS OF A TECHNICAL OR PROGRAMMATIC NATURE?
  
—> Contact: Glenn Schneider at gschneider@mac.com
 

PREVIOUS EFLIGHTS LED BY GLENN SCHNEIDER

RELATED INFORMATION
GO TO:
ROY MAYHUGH'S ASTRONOMY VACATIONS WEB SITE
GLENN SCHNEIDER'S HOME PAGE AT STEWARD OBSERVATORY


Last page update: 03 Sept 2009 14:06 MST