Astronomer Helps Navigate Historic Solar Eclipse Flights Over Antarctica

University of Arizona astronomer Glenn Schneider helped plan the two aircraft intercepts of the Nov. 23 total solar eclipse, which won't be visible from land anywhere else on Earth.

Schneider will be in the navigator's seat on one of the aircraft, a chartered Qantas Boeing 747-400. It will carry solar eclipse chasers, scientists, photographers, amateur astronomers and tourists on a 14-hour, nonstop roundtrip flight out of Melbourne, Australia. Schneider has worked with Qantas pilots for the past several years in planning the special flight, arranged through Croydon Travel of Melbourne. He will assist the flight crew in navigating the plane through the moon's shadow during "totality," when the moon entirely blocks the sun.

Passengers in the moving aircraft might see totality for as long as 2 minutes, 36 seconds, if there is little or no wind, compared to less than 2 minutes that totality will last at ground sites. The eclipse occurs at 22:40 Universal Time (5:40 p.m.Eastern time), which is 9:40 a.m. Monday, Nov. 24, Melbourne time.

Schneider developed computer software called "EFLIGHT," a navigational program specifically for flying aircraft into the path of total eclipses. It helps pilots respond to real-time, in-flight conditions to get the best possible "totality run." He used EFLIGHT in planning two previous airborne missions that intercepted the total solar eclipses of Oct. 3, 1986, and June 30, 1992. He also planned to use EFLIGHT on the Concorde for a 2001 eclipse. But that flight was canceled after Air France grounded its Concorde fleet following a crash.

For the Nov. 23 eclipse, pilots on two aircraft will use EFLIGHT in their flight management systems. Schneider and the Qantas pilots conducted a dry-run test on the system last July in a 747 flight simulator. Meanwhile, Sky and Telescope magazine and Travelquest International chartered a Lan Chile Airbus A340 for the eclipse. That plane will fly out of Punta Arenas, Chile. Sky and Telescope recruited Schneider to assist planning its flight, too.

On the Qantas eclipse flight, Schneider will operate four cameras on a gyro-stabilized platform suspended over the flight deck by bungee cords. The cameras will be controlled by computer software that Schneider wrote, and a Sony video camera will guide the platform by feeding images to the computer system. Three still photo cameras will be used to photograph the eclipse: a Pentax ZX-5n equipped with a 500 mm f/5.6 lens, a Nikon F5 equipped with Nikon Vibration-Reduction 80-400 mm zoom, and a Santa Barbara Instrument Group 1024 x 1024 CCD digital camera with a 300 mm lens and special green filter. The filter is used to create better images of the sun's inner corona.

The camera equipment was provided by collaborators including Jay M. Pasachoff of Williams College. Pasachoff, who chairs the International Astronomical Union's Working Group on Eclipses, will be on the Qantas flight.

Schneider occasionally may have to blow on the camera platform if it begins to drift away from the 16-by-27-inch window that the cameras peer through. A breath of air is all that's needed - touching the platform would send it swinging.

The B747-400 will fly at about 470 nautical mph at 38,000 feet. It will fly within a kilometer of the center of the moon's shadow, within 100 meters of its target vertical position, and within a 6-second time margin.

The moon's shadow, which is about 64 nautical miles across, moves at 2,200 nautical mph, or about 4-and-one-half times faster than the airplane. It will overtake the plane from behind.

"The moon's shadow will be projected down below us onto the cloud tops, so the snow and ice will be dark," Schneider said. "There will be no reflected sunlight coming back up. The sky will be black."

Scientists plan to make some unique light-scattering measurements on Earth's upper atmosphere during the flight, Schneider said. They will use the moon's shadow as an illumination probe to get information on particle distribution that they can't get with remote sensing or LIDAR.

Schneider is an associate astronomer at the UA Steward Observatory. He also is the project instrument scientist for the NICMOS, the instrument that gives the Hubble Space Telescope its infrared vision.

Schneider describes himself as an "umbraphile," literally a "shadow lover," one who is "addicted to the glory and majesty of total solar eclipses." Umbraphillia "is not only an addiction, but an affliction, and a way of life, the real raison d'etre for many of us," Schneider said. Umbraphiles are commonly called "solar elipse chasers," people who once every 16 months or so "will drop whatever they are doing and trek by plane, ship, train, foot, and camel-back to gather along a narrow strip in some remote God-forsaken corner of the globe."

Because Schneider is willing to travel, he has seen 23 eclipses since 1970 and been clouded out only three times.

But travel often entails killer jet lag. The 14-hour eclipse flight returns to Melbourne at 3 p.m. local time. Schneider then will repack the cameras, gryo platform, computers, inverters, power supplies, etc. into shipping crates to catch an 8 a.m. flight the following morning -- the start of his 28-hour trip back to Tucson.

"I missed Thanksgiving last year because I was in the Australian outback for the last eclipse, and I promised my wife I'd be home for Thanksgiving this year," he said.

Macintosh users can download Schneider's software for photographing a solar eclipse, called "Umbraphile," from the Internet for free. Given the particulars of an eclipse, the program computes an exposure sequence table synced to Universal Time and automatically fires the camera at correct exposures. The software is online athttp://balder.prohosting.com/stouch/UMBRAPHILE.html

Related Web sites

http://nicmosis.as.arizona.edu:8000/ECLIPSE_WEB/ECLIPSE_03/ECLIPSE_03.html

http://www.eclipses.info