TSE 2015: 20 March 2015 Total Solar Eclipse

Two Amazing Flights  into The Darkness of the Lunar Umbral Shadow
From the Pristine, Dark, Cloud-Free Free Skies 37,000 feet AMSL

~ 3m 49s of prolonged Greatest-Eclipse Totality @ 64° N Latitude
and
Equinoctial Sunrise Totality (~ 1m 55s) from the Geographic North Pole



THE TSE 2015 PATH OF TOTALITY

A truly remarkable, but geographically remote, total solar eclipse will occur on the 20 March 2015 with the Sun on the celestial equator at the vernal equinox, as the Moon's umbral shadow traverses a narrow path for 1 hour and 5 minutes over the North Atlantic and Arctic Oceans, spectacularly ending with a blackened sunrise at the geographic North Pole. The path of totality, the region on the Earth's surface where the Sun will be totally obscured by the Moon, begins at sunrise over the cold waters of the north Atlantic Ocean 650 km east of Newfoundland where the eclipse centerline then at 09:13 UT is 600 km is south of the southern tip of Greenland.  The path then sweeps north eastward passing, but missing, the east coast of Iceland in route, literally, to the "top" of the world at the North geograhic pole.


The TSE 2015 path of totality (left: blue arc, right: gray arc) with the planned points of mid-eclipse intercept for our "to the max" (red) and
North Pole (left: green) EFLIGHT viewing locations.
(Maps: left - adapted from Espenak and Meeus 2006, 5MCSE; right - adapted from HMNO)


TSE 2015 finds landfall only on two north Atlantic island locations. The first, to the south-east of the centerline of the path of totality, on the Faroe Islands (latitude 62° N) where the Sun will fall into total eclipse for a maximum duration of off-centerline totality of 2m 25s on the western side of the tiny island of Mykines. The second, as the centerline of the path of totality traverses Svalbard/Spitzbergen (latitude ~ 79° N) giving rise to a nearly equal maximum duration of on-centerline totality 2m 26s from the island's north coast.  Both island locations, while wonderful locations to visit and explore, are very likely contra-indicated as eclipse viewing sites in mid-March due to the strong prevalence of clouds with high probabilities of obscuration with the Sun at low elevation angles above the local horizons. Some eclipse chasers will undoubtedly make the attempt, and we wish them great luck – but the assured solution for TSE 2015 observers is to take to the skies above the prevailing weather. 

The point of greatest eclipse,
250 km north of the Faroe Islands in the Norwegian Sea between Iceland and Norway, is where the Moon's shadow is nearly simultaneously moving most slowly across the Earth and the duration of totality is at a maximum anywhere along the path of totality (2m 47s) lie.  Further north, after passing over Svalbard/Spitzbergen, the Moon's shadow streaks northward to the geographic North Pole where at 10:17 UT with (from sea-level) the horizon bifurcating the fully-eclipsed Sun as it very slowly rises and the Pole is plunged into a prolonged total eclipse induced twilight for 1m 55s. 

The two ideal locations on Earth for eclipse-chasers
with different but symbiotic eclipse viewing goals, if concerns of weather and logistics for their remoteness and isolation could be overcome, are at the point of greatest eclipse (with also the sun "highest" in the sky during totality for TSE 2015), and exactly at the geographic North Pole to witness a very rare equinoctial totality at polar sunrise.  Our TSE 2015 EFLIGHTS "64N" and "90N" uniquely enable these rare opportunities.


EFLIGHT 2015 64N and 90N

For TSE 2015 we are now planning two spectacular, but phenomenologically distinct, airborne eclipse expeditions to satisfy the goals and objectives of two schools of umbraphiles – those called by the siren's song of "duration, duration, duration" and those enticed by the unparalleled location and vista at the top of the world, both from a venue > 11 km above the surface of the Earth.  Both "EFLIGHTS" (designated 64N and 90N for their mid-eclipse latitudes) will launch {from Dusseldorf, Germany,} with optimal eclipse viewing as the driving requirement for defining all details of their flight plans.  For both, the totally eclipsed Sun will be positioned "straight out" the main cabin passenger windows for optimum viewing of the corona enshrouded Sun and umbral shadow on the sea/ice below and eclipse-darkened sky above from an altitude of ~ 37,000 ft AMSL where we will be
above any obscuring cloud and otherwise disturbing weather below.

Viewing a total solar eclipse, and the sweep of the Moon's umbral shadow as it races across (and above) the Earth, as seen from such a lofty height as enabled by our EFLIGHT aircraft, is magnificent beyond description.  As seen from 37,000 feet above the surface of the Earth, the apparent horizon is 377 km (234 miles) away and depressed by 3.4° compared to sea level.  Looking along the apex of the lunar umbral cone toward the eclipsed Sun at mid-totality, or along its outer periphery as the shadow sweeps over the aircraft coincident with the instants of second or third contacts, the curvature and gradure of the umbral shadow boundary (i.e., the "shadow ellipse") is stunningly apparent. At polar latitudes, the high reflectivity of the polar ice below accentuates the stark contrast between the eclipse-darkened regions within umbral shadow, and those illuminated by the Sun beyond the shadow's edge. Being above more than 3/4 of the Earth's atmosphere the corona of the Sun is presented with contrast and clarity in the rarefied air incomparable to ground-based venues at the bottom of a bubbling pool of atmospheric turbulence.  (See below, shadow and corona photos taken from our predecessor TSE 2008 flight; similarly executed over the Arctic Ocean).


Stunning stratospheric views (and photographs) of the 01 August 2008 Total Solar Eclipse, at 82° N latitude, 11 km above the Arctic Ocean, were uniquely obtained on board
our  LTU/AirBerlin A330-200 EFLIGHT 2008 aircraft.  In planning our 2015 EFLIGHTS we draw significantly upon the successes of this historical predecessor implemented
also in partnership with Deutsche Polarflug under the experienced guidance and technical leadership of Dr. Glenn Schneider (Steward Observatory, The University of Arizona).



Flight #1 — EFLIGHT 2015 64N

To The Max!


Flight #1 (64N) will be aboard an A320 or "similar" eclipse-suitable narrow-body jet aircraft, providing the best and most cost-effective viewing-window to seat-count  ratio, to be used to centrally intercept the Moon's shadow at the point of greatest (globally maximum) eclipse at (nominally) 37,000 AMSL.

With at-altitude mid-eclipse occurring at 09h 45m 38s UT, the duration of totality will be stretched to approximately 3m 49s, more than a minute longer than would be possible from a hypothetical Ocean-going vessel 11 km below, and appx. a minute and a half longer than will be seen from the Faroe Islands (should clouds below us cooperate for ground-based observers located there).

With a max-eclipse intercept point of (64° 13' 04.0" N, 06° 09' 18.0" W), the fully-eclipsed Sun will stand 18.6° above the astronomical horizon (22.0° above the apparent horizon) allowing very easy and comfortable viewing out the aircraft sun (right) side passenger cabin windows, individually or shared with a window-viewing partner.

{For this flight, like the recent record-setting TSE 2010 EFLIGHT over the south Pacific, we are looking into the possibility of removing seats from the sun-side of the aircraft to facilitate even better full-window access to all eclipse observers and to optimize their viewing opportunities}.

For those who want the maximum possible duration of totality EFLIGHT 2015 64N, this appx 5 hour round-trip flight is it!


*with no wind and assuming a nominal ground speed of 470 nm/hr
Flight # 2 — EFLIGHT 2015 90N

To the Top of the World!


Flight #2 (90N) offers a shorter duration of totality, but advantageously exploits the capabilities of longer-haul distance capabilities of an A3330 (or similar) wide-body jet  aircraft to provide a topographically remarkable (and to date historically unique) observing venue. 

Eclipse-chasers onboard will witness totality at Sunrise directly over the North Pole!


With the Sun literally on the celestial equator, at sea-level the Sun will be on the horizon, but viewed from the pristine, clear, skies of the polar north stratosphere at 37,000 ft the Sun will hover 3.4° above due to the curvature of the Earth.  The Moon's conical shadow will sweep nearly parallel to the horizon nearly 400 km away as an inverse searchlight beam blackening the skies above and North Pole below. Those on our aircraft will fall into totality at, literally, the top of the world arresting the once-a-year dawn for 1m 55s of suspended totality centrally framed at 10h 17m 06 UT.

{EFLIGHT 2015 90N will also offer "anti-sun" viewing of  polar sunrise lunar-shadow phenomenon to non-totality viewing "flightseeing" passengers left side of the aircraft  for all (thus reducing the otherwise higher per person cost of our special charter to eclipse-chasers)}.

All on-board will witness the post-totality partially-eclipsed solar crescent hugging the horizon as the aircraft descends to low-altitude for a closer view of the North pole after the big event. 

{Further we are looking into the possibility for a short stop-over in Longyearbyrn (78° N) on Spitzbergen to stretch our legs in the world's northern most inhabited location before returning "home" to
Dusseldorf.



TOP 10 REASONS FOR A HIGH LATITUDE STRATOSPHERIC ECLIPSE FLIGHT
DEPLOYMENT/RELOCATION FLEXIBILITY
To Find the BEST Spot(s) in the Area of Operations for Observing
CLOUD OBSCURATION AVOIDANCE*
High Latitude Stratosphere Stratosphere: 99.99% -- Virtually Assured
TOTALITY PROLONGATION FOR MAXIMUM ECLIPSE (Flight #1)
Aircraft Speed Extends the Duration of Totality
SKY TRANSPARENCY
Significantly Improved -- Low Particulate Scattering
SKY DARKNESS
Much Higher Contrast Coronal Visibility and to Larger Distance
IMPROVED ASTRONOMICAL SEEING
"r_naugh" Decreases with Increasing Altitude
REDUCED ATMOSPHERIC TURBIDITY
Vorticity & Sheer Decline in Power Above Tropopause
PANCHROMATIC VISIBILITY
IR and UV "Windows" Open Up or are Extended
UNPARALLELED HORIZON  REACH & OBSERVATION VISTA
Apparent horizon 377 km distant, depressed 3.4° (at 37,000 ft)
ESTHETIC, ETHEREAL EXPERIENCE
There is nothing quite like it...



THE "WEATHER" (acuna matata)

At |latitudes| > 60°, such as our 64N and 90N points of mid-eclipse intercept, the tropopausal boundary between the troposphere below (where "weather occurs") and the stratosphere has typical equinoctial heights of < 9–10 km. Polar stratospheric (nacrecous) clouds are extremely rare and only form at very low temperatures (< -78° C) during the polar winter, making the probability of cloud-free eclipse viewing nearly 100% at our flight altitude of 37,000 ft (~11.3 km) at our chosen observing locations.  Of course, we have the luxury (and flexibility) for in situ retargeting of our viewing locations if that is required for any reason, however unlikely. 

At this altitude and latitudes, aerosol scattering of sunlight by airborne particulate is usually extremely low (especially at 90° N), giving rise to an exceptionally dark sky during totality, enabling eclipse viewing with significantly enhanced image contrasts. Moreover, the airmass along the line-of-sight to the Sun is significantly reduced (by ~ 75%), resulting in exceptional sky transparency, greatly reduced atmospheric turbidity, and better astronomical "seeing". 

{At 64° N east of Iceland, the possibility of high-altitude volcanic ash originating in Iceland while statistically small is non-zero.  Thus, we have built our EFLIGHT 2015 64N plan with sufficient flexibility to reach higher latitudes (with somewhat reduced maximum duration of totality) where such particulate are very unlikely to be transported given normal polar wind circulation patterns}.


BASELINE EFLIGHT and ECLIPSE-OBSERVATION ("Totality Run") PLANNING

The detailed definitions of the 64N and 90N flight plans will be developed to optimize the observing opportunities at both locations. In both cases the nominal (baseline) flight plans are built around an eclipse-viewing "totality run" (TR) constrained by celestial mechanics, aircraft operational considerations, and a need to maintain in situ flexibility to implement contingency alternatives.  For early planning and logistical purposes only we presume (1) a flight altitude for eclipse-viewing of 37,000 feet AMSL, with (2) a ground speed of 470 nm/hr and (3) no wind (so ground speed = air speed, and heading = course).  Detailed pre-eclipse flight planning, and in-flight execution, will incorporate and allow for the full range of possible flight levels, air speeds, and wind-vectors that may be encountered in flight to re-optimize the totality runs in situ as may be necessary or desired. 

We define the baseline totality runs such that the aircraft is centrally located at the apex of the lunar umbral shadow (but corrected for the irregular lunar-limb profile) at the topocentric instants of "maximum eclipse" at the chosen intercept points.  We also define the baseline totality runs so that the aircraft velocity vector at mid-eclipse places the Sun "straight out" the right-side windows of the aircraft passenger cabin to provide optimum out-the-window viewing and utilization.  For the
64N flight this orientation also provides a very nearly optimal orientation to prolong the duration of totality to a theoretical maximum anywhere along the path of totality by using the aircraft's speed to (partially) keep pace with the lunar shadow.  With these constraints, we compute, and tabulate below, three key time correlated waypoints for the totality runs that define the lunar shadow intercept and crossing by the aircraft designated C2 (eclipse contact II), MAX (corresponding to the UTC instant of maximum eclipse), and C3 (eclipse contact III).  MAX, in both UTC and lat/long will depend upon the aircraft altitude AMSL.  C2 and C3 will also depend upon the aircraft ground speed and track (i.e., airspeed and winds aloft). 

The (earlier) start of the pre-totality leg of the totality run is be defined by a pre-totality time-correlated waypoint TBD (but probably about 9) minutes before C2. The aircraft is initially positioned on the MAX-eclipse intercept track at the requisite course/heading, distance, and flight-time from the intercept point allowing for airspeed adjustment in the run up to the C2 time-correlated waypoint to compensate for deviations due to actual (vs. predicted) winds aloft (holding the MAX intercept time-correlated waypoint invariant).  After C3 the aircraft will remain on the MAX-to-C3 heading for TBD (but appx 5) minutes to allow viewing of the recession of the Moon's shadow before returning home.


BASELINE TIME-CORRELATED WAYPOINTS and ECLIPSE CIRCUMSTANCES FOR EFLIGHTS 2015 64N and 90N
(Assumes FL 370, Airspeed = Groundspeed = 470 nm/hr, No wind)
Flight #1 – EFLIGHT 2015 64N   Totality Duration: 3m 49.1s    Mid-UT: 09h 45m 37.75s

TRS (C2-9m)
C2
MAX
C3
U.T.
09h 34m 41.2s 09h 43m 41.2s 09h 45m 38.6s 09h 47m 30.3s
Aircraft Lat.
63° 11' 54.94"
64° 02' 18.10" N 64° 13' 04.0" N 64° 23' 14.71" N
Aircraft Lon.
08° 24' 14.83"
06° 34' 07.25 W 06° 09' 18.0"W 05° 45' 22.53" W
Ast./App. Sun Alt. 17.8° / 21.1°
18.6° /  22.0°
18.8° / 22.2°
18.9° / 22.3°
Sun Azimuth 130.2°
134.5° 135.4°
136.4°
Limb Profile Offset
N/A
-1.9s  N/A
-1.8s
Heading/Distance*
43.38°, 70.5 nm
45.03°, 15.33 nm
45.40°, 14.59 nm

 *provided for info only -- navigation by time-correlated waypoints
Flight #2 – EFLIGHT 2015 90N   Totality Duration:  1m 55.2s   Mid-UT: 10h 17m 06.0s

TRS (C2-9m)
C2
MAX
C3
U.T. 10h 07m 08.4s
10h 16m 08.4s 10h 17m 15.8s 10h 18m 03.6s
Aircraft Lat. 88° 41' 03.7" N
89° 51' 12.0" N 90° 00' 00.00" N
89° 53' 42.6" N
Aircraft Lon. 62° 36' 36.0" W
62° 36' 36.0" W N/A(1) 117° 23' 24.0" E
Ast./App. Sun Alt. -0.1° / +3.3°
-0.1° / + 3.3°
0.0° / +3.4°
-0.1° / + 3.3°
Sun Azimuth 87.3°
89.5°
N/A(1,2)
35.2°
Limb Profile Offset
N/A
-0.4s
N/A
+0.6s
Heading/Distance* 0.0°, 70.5 nm
0.0°, 8.85 nm
180°, 6.32 nm
 (1) undefined at pole, (2) Longitude of Sub-solar point = 27.39°E, *provided for info only -- navigation by time-correlated waypoints



CONTACT & ADDITIONAL INFORMATION

This page will be updated as plans evolve and mature.  Those with interests in either (or both) of the in-development TSE 2015 EFLIGHTs are encouraged to contact:

Dr. Glenn Schneider
Steward Observatory, The University of Arizona
Tucson, arizona 85721 USA
email: gschneider@as.arizona.edu
Telephone: 520-621-5865

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last update: 23 June 2011