01 August 2008
North Polar Total Solar Eclipse Flight 

Frequently Asked Questions

Click HERE for the baseline/nominal flight plan

Click HERE for more information on the eclipse flight

Q. When is the next total solar eclipse?

A. The next total solar eclipse will occur on 01 August 2008.  The Moon's umbral shadow will "touch down" on the Earth at 09h 24m Universal Time (U.T.) and "lift off" at 11h 21m U.T.

Q. How often do total solar eclipses occur?

 A. On the long-term average, a total solar eclipse is visible somewhere in the world about once every sixteen months.  However, the overlap between the "cycles" of solar eclipses is complex.  The previous total solar eclipse occurred two and a third years earlier on 29 March 2006.  The one following the 01 August 2008 eclipse, only 354 days later on 22 July 2009 will be the longest duration total solar eclipse (6m 37s at eclipse maximum) until 13 June 2132.  Also, on average, any given spot on the Earth will see a total solar eclipse about once every 360 years.  However, eclipse paths can cross specific locations much more frequently (for example the 2001 and 2002 eclipse paths crossed in Southen Africa), and those living in the right location saw both of them.
Q. Where will the 01 August 2008 total solar eclipse be visible?

A. The "path of totality", the region on the Earth's surface which will be swept by the Moon's umbral shadow and where the total phase of the eclipse can be seen, begins in the Canadian Arctic, sweeps the north coast of Greenland and passes only 6.2° from the North Pole before turning southward.  The path of totality then crosses between, and grazes the northern islands of Kvitoya and the south western tip of Franz Joseph Land (Nagurskoye) and over Nova Zemlya before traversing northern Russia on its southward journey eventually passing centrally over the Novosibersk, the 3rd largest city in Russia and capital of Siberia.  The Moon's shadow then moves over the region where the borders of Kazakhstan, Mongolia, China, and Russia all nearly come into confluence.  Straddling the western edge of Mongolia the path of totality turns southeastward and ends in Sunset in eastern China.

Q. Where along the path will you observe the 01 August 2008 total solar eclipse?

A. From the high polar north, at a latitude of appx 83°N, north of Svalbard, at mid-eclipse 444 nautical miles fron the geographic North Pole from a jet aricraft at 37,000 feet above the Arctic Ocean.

Q. Why that location, and why from an aircraft?

A. Observing from a high-altitude aircraft provides the opportunity to get above clouds and bad weather than might interfere with viewing the eclipse (e.g., from Novosibersk, the "odds" of seeing the eclipse due to cloud obscuration is just about 50%).  At 83°N, in mid-late summer, at 37,000 feet clear skies are virtually assured. The stratification of the Earth's atmosphere is latitude dependent.  At lower latitudes the top of the troposphere ("where weather occurs") ranges from 12 - 17 km, but the tropopause (the boundary between the troposphere and the stratosphere) declines to only 6-9 km nesr the poles during the summer months.  Flying at 37,000 ft (~ 11.7 km) we will be well into the stratosphere and well above any clouds that can form only at lower altitudes.  At this latitude, also, the sky is extremely clear -- and dark once the sunlight is extinguished -- due to very low levels of airborne particulates (light scatterng particles) in the upper atmosphere.  Using an aircraft will also prolong the duration of totality, the time we will spend in the Moon's shadow viewing the total eclipse.

Q. Has a total solar eclipse ever previously been observed so close to the North Pole?

A. There is no record of any solar eclipse observations as far north as we are now planning for the 01 August 2008 total solar eclipse flight, only about 7° from the North pole.

Q. Are eclipses in the polar regions rare?

A. No, but accessibility is difficult. Until this juncture in time (and technology) very high latitude (north or south) total solar eclipses have been elusive.  The total solar eclipse of 23 November 2003 was the first in history to have been observed from the Antarctic.

Q. What kind of aricraft will we use?

A. We will use an Airbus A330-200 twin-engine long-range aircraft certified for ETOPS (Extended-range Twin-engine Operational Performance Standards) flight which is extremely well suited to our needs. The aircraft has been chartered from LTU/airberlin and the flight plan optimized specifically for the purpose of flying into the Moon's shadow and viewing the total solar eclipse. All of the many detailed, and unusual, requirements of our flight have been evaluated and satisfied (including all identified contingencies to minimize risks to eclipse viewing and optimize the observing experience) with arrangements by the air charter company Deutsche Polarflug.  Deutsche Polarflug (AirEvents)  has previously operated successful North Pole siteseeing flights with the same aircraft.

Q. Will the eclipse be observed from any other aircraft in the polar region?

A. At this time, we know of no other aircraft.

Q. How many "eclipse chasers" will be on-board our aircraft?

A. Only those seats immediately adjacent the (two-seat wide) windows on the starboard (right) side of the aircraft will be used by eclipse chasers to view the eclipse.  Approximatley 55 people will be observing totality through whe windows adjacent to those seats (some used individually, some sharing, as per individual preferences and arrangements made by each).

Q. Will there be others on the aircraft?

A. Obviously the flight crew, with Cpt. Wilhelm Heinz as Pilot in Command, cabin attendents, and three representatives of Deutsche Polarflug (Airevents; the German based charter company who worked with TravelQuest in arranging the flight with LTU/airberlin).  We will also have Dr. Glenn Schneider from the University of Arizona's Steward Observatory who has worked on the detailed formulation of the flight plan and Kelly Beatty, executive editor of Sky & Telescope magazine.  Both are veteran eclipse chasers and will be onboard (and available in Dusseldorf the day before the eclipse) to assist flight-bound eclipse chasers.

Q. When will we see totality?

A. Our planned mid-eclipse intercept, when our LTU/Airberlin A330-200 aircraft will be co-located in the center of the Moon's shadow, is at 09h 43m Universal Time (note that UT = German summer time - 2 hours).  We remain flexible, and can centrally intercept the shadow earlier in time (closer to the coast of Greenland) or later (closer to Franz Joseph Land), in the very unlikely event of turbulent air or any other reasons that might arise in situ suggesting a better location to view the eclipse.

Q. How long will totality last?

A. In the absence of any winds, as seen from our aircraft with a mid-eclipse at 22h 44m UT totality will last will last 2m 56s.

Q. Does the aircraft's speed prolong the duration of totality compared to a ground-based observer?

A. It does. From the Arctic Ocean below, totality (at the location where mid-eclipse occurs at 09 h43m U.T.) will last only 2m 12s, forty-four seconds shorter than we will experience in our aircraft.   Note that the difference is longer than both the maximum duration of totality experienced during the recent total solar eclipse from Australia on 04 December 2002, and anywhere along the path of the 04 April 2005 total solar eclipse, in the middle of the South Pacific Ocean.

Q. How fast will the aircraft be moving?

A. Our true airspeed will be 483 nautical miles (894.5 kilometers per hour; Mach 0.85) during the planned 13 minutes of the "totality run". 

Q. How fast will the Moon's shadow be moving?

A. At the 09h 43m UT instant of mid-eclipse the Moon's shadow will be moving at: 4,313 kilometers per hour (2,383 nautical miles per hour) relative to the Earth's surface.

Q. How does the aircraft's speed help us?

A. The aircraft will be moving with a speed of appx 20.3% of the lunar shadow (at 09h 43m U.T.).  Our aircraft heading is optimized to enable the best visibility of the eclipse out the (sun side) passenger cabin windows, which is not quite in the same direction as the motion of the Moon's shadow (we "cross" centerline at an angle, rather than flying along it). Nonetheless, we do get a "boost" that prolongs the duration of totality relative to a stationary observer and the Moon's shadow will overtake and pass us significantly more slowly than a observer on the Arctic Ocean below.

Q. In detail, what are the "local" circumstances of the eclipse as seen from the aircraft, where will we see the eclipse?

A: For the following "baseline" flight parameters:

 U.T. Intercept:  09:43:00 UT
 Flight Altitude:  37000ft
 Heading:           71.9°
 Air Speed:      483.0nm/h
 Wind Speed:       0.0nm/h
 Wind Direction:      0.0°

the circumstances of the total phase of the eclipse are as follows:

  UNIVERSAL TIME = 09:43:00 UT
  LATITUDE  = 82° 34' 54.4"S

  LONGITUDE = 18° 42' 27.9"N
  Solar Altitude = 24.9°
  Solar Azimuth  = 162.0°

   UNIVERSAL TIME     =  09:41:32.5 UT
   AIRCRAFT LATITUDE  =  82° 31' 10.2"N
   AIRCRAFT LONGITUDE =  17° 17' 19.9"E
   Solar Altitude =  24.9°
   Solar Azimuth  = 160.1°
   Position Angle of Contact = 119.9°

   UNIVERSAL TIME     = 09:44:28.4 UT
   AIRCRAFT LATITUDE  = 82° 38' 43.7"N
   AIRCRAFT LONGITUDE = 20° 09' 32.3"E
   Solar Altitude =  24.9°
   Solar Azimuth  = 163.9°
   Position Angle of Contact = 283.6°

Conditions in flight may call for a mid-eclipse intercept at a different altitude or Universal Time. 

Q.  Is our intercept at the point of the longest possible duration of the total phase of the eclipse?

A. No, this occurs at a location corresponding to a mid-eclipse near 10h 21m 08m U.T in northern Russia near Nadym.  From the ground the duration of totality on centerline there will be 28.7 seconds shorter than we will experience from the air at 09: 43 UT at 82° 35'N latitude.

Q. At what altitude will we view totality?

A. We will observe the eclipse at the maximum altitude which can be supported at this phase of the flight, without necessitating using any fuel margins. This will depend somewhat on the actual pre-eclipse low-level siteseeing flight plan over Svalbard, as well as weather en route and winds aloft.  The "baseline" plan for the eclipse observation described HERE is for 37,000 feet above mean sea level.  If conditions permit we will observer the eclipse higher altitude, (or if necessary at a slightly lower altitude) which will change the details of the local circumstances by a small amount.   This possibility is anticipated and is easily accommodated in real-time with no significant change in the duration or viewing aspects of the total eclipse.

Q. At that altitude what sort of winds are we likely to encounter?

A. Our intercept position corresponding to the aircraft being centrally located in the Moon's shadow at 09h 43m U.T., was also chosen to locate the aircraft sufficiently far from the Greenland coastal buffer zone (ice/sea interface) wind effects. The dominant wind pattern in the northern polar stratosphere at this time of year produces very mild winds, typically ~ 10 knots or less with little vertical mixing. Infrequent anomalous conditions can arise ("climate is what you expect, weather is what you get") and we are prepared to relocate our eclipse intercept point if required. 

Q. How would such winds (or "abnormal" winds) affect the duration of totality?

A. Because the Moon's shadow is moving much faster than the aircraft, the change in  relative speed even with high winds does not have a big effect on the duration of totality.  For example, a headwind of 100 nautical miles per hour (much more than is expected) would reduce the duration of totality by only 10.1s (to 2m 45.8s), whereas a comparable tailwind would increase the duration of totality to 3m 06.2s.

Q. How high will the Sun be above the horizon during totality?

A. The Sun will be 24.9 degrees above the astronomical horizon at mid-eclipse.  At 37,000 ft, the apparent horizon is depressed by 3.4 degrees, so the Sun will appear to be 28.3 degrees above the apparent horizon.  This is sufficienly high to fully take advantage of the viewing conditions afforded by the rarified air at 37,000 ft, and simultaneously comfortably low for viewing the eclipse through the aircraft windows.

Q. What is the "horizontal viewing angle" of the Sun during totality - along the horizon?

A. The eclipse intercept is planned such that the Sun will be "straight out" the starboard (right) side cabin windows, i.e., 90-degrees to our direction of flight.  This will maximize visibility of the eclipse, and shadow phenomenae out the cabin windows.

Q. How clear/dark will the skies be at 37,000 feet?

A. Where weather is concerned one can never be 100% assured.  However, at 37,000 feet our aircraft will be above more tan 3/4ths of the Earth's atmosphere,  and at these polar latitudes airborne particulates are extremely sparse.  We will be and several kilometers above the tropopause,  the boundary between the troposphere below ("where weather occurs") and stratosphere in which we will be flying.  Late summer polar stratospheric clouds are extremely uncommon (almost, but not completely, impossible) at our eclipse-intercept latitude. The sky transparency along the line-of-site to the sun should be spectacular, the turbidity very low and the "astronomical seeing" extraordinary.  The sky, during totality, at 37,000 feet should be exceptionally dark, and the view of the lunar shadow in the sky above, and projected on the ground below, will be incomparable.  For an illustrative examples SEE THESE PHOTOGRAPHS taken out the cabin windows of the passage of the lunar shadow during the 23 November 2003 total solar eclipse from 35,000 ft above Antarctica (top - one minute before and after totality, bottom at mid-eclipse).   High-altitude particulates, which cause light-scattering from the illuminated regions outside of the shadow, over the high polar north, are significantly more sparse than at lower latitudes.

Q. Do we have a contingency option in the event of very rare obscuring cloud cover?

A. We have defined an area of operations, where we can elect to observe totality over a wide area from near the coast of Greenland to near the coast of Franz Joseph Land.  We can elect to change our position and still optimally intercept the Moon's shadow on centerline at mid-eclipse anywhere along that portion of the path of totality.  See this schematic map that shows our defined area of operations.  The black line is our nominal (baseline) flight plan, the dashed red lines show the extrema that we are contemplating if the need for relocation should arise.

Q. What if the flight take-off is delayed or we encounter strong head winds on the flight out of Dusseldorf?  Isn't the eclipse intercept time critical?

A. The intercept itself is, but our flight plan has both contingency and margin built in, and we remain highly flexible. The eclipse-observation portion of the flight is nominally planned to be conducted after about an hour and twenty minutes hours of low-altitude sightseeing in the Svalbard region.  That time (plus an additional appx 10 minutes) can be used in contingency on the ground or in the air.  If we are delayed by as much as about an hour and a half we can head straight to eclipse and achieve an optimal flight through totality.

Q. If unforeseen contingencies arise can we re-plan the eclipse observation in "real time"?

A. The flight pre-planning, including baseline and contingency (alternate) scenarios have been carried out using a highly specialized software package called EFLIGHT which symbiotically synthesizes dynamical ephemerides generation for the eclipse from a moving platform with aircraft navigation information.  EFLIGHT (which is fully described HERE) was designed for in situ on the aircraft flight deck and real-time airborne eclipse navigation.  It will be used in this manner on the 01 August 2008 flight to "guide" the aircraft to an optimal "totality run" and eclipse intercept.

Q. Will we see the partial phases of the eclipse from the aircraft?

A. We have made no special plans, nor levied any requirements on the flight profile for viewing first/fourth contacts or most of the ingress/egress phase of the partial eclipse, as this nominally will occur during the sightseeing and cruise phases of the flight.  The orientation of the aircraft, as it maneuvers for pre-eclipse low-altitude siteseeing over Svalbard and post-eclipse at the North Pole, will likely allow some serendipitous viewing of the partial phases.  About a half an hour before totality (the exact time dependent upon the position of the aircraft) we will break off the site-seeing portion of the flight and head to a pre-determined base leg to fly  just ahead of the start of the planned flight path for the "totality run".  Ten minutes before mid-eclipse we will complete a heading alignment maneuver to put the aircraft on a nearly "straight line" course for a mid-eclipse intercept with the center of the umbral cone at 09h 43m.  During the run up to totality the Sun will be essentially perpendicular to the direction of flight, "straight out" the left side cabin windows at mid-eclipse. This will provide an opportunity to view (and prepare photographic equipment during) the latest stages of the partial ingress phase of the eclipse, including the approach of the umbral shadow and the onset of second contact.  After third contact the aircraft will continue on the totality run track for a few minutes minutes to view the first stages of the partial egress phase of the eclipse and the recession of the lunar shadow before heading due north to the North Pole.

Q. What are the windows like?  Will I get a good view?

A. The aircraft windows are of good optical quality for visual, and low to moderate power binocular observations and/or photography.  We have arranged to have the windows cleaned to our specifications during pre-flight servicing in the evening before our eclipse flight.  The windows are 22 cm wide and 33 cm high.  Only those sunside window-row seats with immediate access to one or more windows by the window seat have been sold to eclipse-viewers.  The
Deutsche Polarflug representatives on-board will set the seat back tilt angles for specific rows to maximize the window accessibility for all eclipse viewers.  Passengers sharing a sun-side seat row need to individually work out how they will share their window(s) during the eclipse.  The cabin interior lights will be extinguished during totality to eliminate glare or reflections on the window surfaces.

Q. Can I get "good" photographs of the eclipse out of an aircraft window?

A. Yes, but take some time and care to think about what camera(s), lens(es), and exposures you might plan - and how you will hand-hold or mount your camera(s).  Consider options like mini-tripods or removable suction cup fixture mounts (that can be affixed to the aircraft wall) or suspended by a "bungie cord" to relieve weight-fatigue in your hands.  High speed film (for those using film) or high sensitivity digital exposures and vibration reduction or image stabilization lenses are very useful and helpful.  As a picture is worth a thousand (or more) words. HERE is a composite image of the 23 November 2003 total solar eclipse corona from images taken by David Finlay through a similar aircraft cabin window as processed by Miloslav Druchmuller.

Q. I still have more questions of a "technical" nature regarding this eclipse and the planned flight.  How can I get answers?

A. Send email to: Glenn Schneider (open email window to: gschneider@mac.com)

Last updated: 20 June 2008