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The telescope is within the rectangular black hole on the side of the C-141A KAO aircraft. Credit: NASA.

Astronomy that benefits from using either an airborne observatory or such a telescope or detector system is airborne astronomy.

Airborne observatory[edit]

An airborne observatory is an airplane or balloon with an astronomical telescope. By carrying the telescope high, the telescope can avoid cloud cover, pollution, and carry out observations in the infrared spectrum, above water vapor in the atmosphere which absorbs infrared radiation.

Observation posts[edit]

"El Caracol" observatory at Chichen Itza, Mexico is shown. Credit: Fcb981.

An observation post, temporary or fixed, is any pre-selected position from which observations are to be made - this may include very temporary installations or even an airborne aircraft.[1][2]


Two photographs were taken on 1939 April 29, about 10:20 A.M. EST of a meteor train. Credit: John H. Spikes and D. Z. Zimmerman.{{fairuse}}
The image shows the first film ever of a meteor plunging down at terminal velocity. Credit: Anders Helstrup / Dark Flight, montage, Hans Erik Foss Amundsen.

Starting on November 16, 1935, at 1:00 A.M., the American Airlines Douglas aircraft took off from Chicago and rose to 8,000 feet. "I had a view of the sky between altitudes 20° and 65° extending over 200° in azimuth through the windows of the pilots' compartment. Leo was in sight all of the time. [...] The pilots, Mr. Hiram W. Sheridan and Mr. William H. Records, and I saw only three meteors on the Chicago-Detroit leg of the journey. [...] After a delay of about one hour in Detroit [the aircraft took off again and rose] to about 7500 feet. [...] we saw not a single meteor. [On the return flight from Newark, New Jersey, directly to Chicago the aircraft maintained an altitude of 11,000 feet.] Only three meteors were seen during the flight from Buffalo to Chicago. Two of these were moderately bright Leonids which flashed across Ursa Major."[3]

"Two photographs, taken 1939 April 29, by Mr. John H. Spikes (photographer [about 10:20 A.M. EST]) and Capt. D. Z. Zimmerman (pilot [a few minutes later]), from an altitude of 9,300 feet about 20 miles east of Salem, Alabama, show what the writer interprets as a meteor train. The train is about 13° long on the first picture and 8° on the second."[4]

In the second photograph, there are "marked changes, especially apparent doubling and twisting."[4]

"A skydiver may have captured the first film [image is second down on the right] ever of a meteorite plunging down at terminal velocity, also known as its “dark flight” stage."[5]

"The footage was captured in 2012 by a helmet cam worn by Anders Helstrup as he and other members of the Oslo Parachute Club jumped from a small plane that took off from an airport in Hedmark, Norway."[5]

“It can’t be anything else. The shape is typical of meteorites -- a fresh fracture surface on one side, while the other side is rounded.”[6]

“It has never happened before that a meteorite has been filmed during dark flight; this is the first time in world history.”[6]

"Having the rock in hand would certainly help. But despite triangulations and analyses, Helstrup and his recruits still haven’t found it."[5]

Cosmic rays[edit]

"By the total exposure of 5865.7 m2·hour·str on DC-8 [airplane at 260 gm/cm2 altitude], we have obtained hadronic and gamma-ray family spectra [from cosmic rays]."[7]


Space weather conditions are associated with solar activity. Credit: Daniel Wilkinson.{{free media}}

The "effect of time-variations in galactic cosmic rays on the rate of production of neutrons in the atmosphere [was studied using] a series of balloon and airplane observations of the [fast neutron] flux and spectrum of 1-10 MeV neutrons, in flights at high geomagnetic latitude, during [quiet times as well as during Forbush decreases, which are rapid decreases in the observed galactic cosmic rays following a coronal mass ejection (CME), and solar particle events for] the period of increasing solar modulation, 1965-1969. It also included latitude surveys in 1964-1965 and in 1968."[8]

In the image on the right for Forbush decreases, data include GOES-15 X-rays, energetic particles, and magnetometer. Cosmic Rays from the Moscow station show a Forbush Decrease.

Gamma rays[edit]

Airborne gamma-ray spectrometry is now the accepted leading technique for uranium prospecting with worldwide applications for geological mapping, mineral exploration & environmental monitoring.

On June 19, 1988, from Birigüi (50° 20' W 21° 20' S) at 10:15 UTC a balloon launch occurred which carried two NaI(Tl) detectors (600 cm2 total area) to an air pressure altitude of 5.5 mb for a total observation time of 6 hr.[9] The supernova SN1987A in the Large Magellanic Cloud (LMC) was discovered on February 23, 1987, and its progenitor is a blue supergiant (Sk -69 202) with luminosity of 2-5 x 1038 erg/s.[9] The 847 keV and 1238 keV gamma-ray lines from 56Co decay have been detected.[9]

"Gamma rays at energies of 0.3 to 8 megaelectron volts (MeV) were detected on 15 April 1988 from four nuclear-powered satellites including Cosmos 1900 and Cosmos 1932 as they flew over a [balloon-borne] double Compton gamma-ray telescope."[10]


The SOFIA observatory is flying with 100% open telescope door. Credit: NASA.

The Gerard P. Kuiper Airborne Observatory (KAO) was a national facility operated by NASA to support research in infrared astronomy. The observation platform was a highly modified C-141A jet transport aircraft with a range of 6,000 nautical miles (11,000 km), capable of conducting research operations up to 48,000 feet (14 km). The KAO was based at the Ames Research Center, NAS Moffett Field, in Sunnyvale, California. It began operation in 1974 as a replacement for an earlier aircraft, the Galileo Observatory, a converted Convair CV-990 (N711NA).

The "Stratospheric Observatory for Infrared Astronomy [(SOFIA) is] mounted onboard a Boeing 747SP. [...] SOFIA’s 2.7 m mirror and optimized telescope system combines the highest available spatial resolution with excellent sensitivity. SOFIA will operate in both celestial hemispheres for the next two decades."[11]

It has an operating altitude of 12-14 km, 39,000-45,000 ft and a spatial resolution of 1-3" for 0.3 < λ < 15 µm, and λ/10" for λ > 15 µm.[11]


Numerous airborne and spacecraft radars have mapped the entire planet, for various purposes. One example is the Shuttle Radar Topography Mission, which mapped the entire Earth at 30 m resolution.


U.S. Geological Survey aerial electromagnetic resistivity map of the Decorah crater has been produced. Credit: USGS.
  • Buried craters can be identified through drill coring, aerial electromagnetic resistivity imaging, and airborne gravity gradiometry.[12]

At right is a "[r]ecent airborne geophysical surveys near Decorah, Iowa [which is] providing an unprecedented look at a 470- million-year-old meteorite crater concealed beneath bedrock and sediments."[13]

"Capturing images of an ancient meteorite impact was a huge bonus," said Dr. Paul Bedrosian, a USGS geophysicist in Denver who is leading the effort to model the recently acquired geophysical data.[13] "These findings highlight the range of applications that these geophysical methods can address."[13]

"In 2008-09, geologists from the Iowa Department of Natural Resources' (Iowa DNR) Iowa Geological and Water Survey hypothesized what has become known as the Decorah Impact Structure. The scientists examined water well drill-cuttings and recognized a unique shale unit preserved only beneath and near the city of Decorah. The extent of the shale, which was deposited after the impact by an ancient seaway, defines a "nice circular basin" of 5.5 km width, according to Robert McKay, a geologist at the Iowa Geological Survey."[13]

"Bevan French, a scientist the Smithsonian's National Museum of Natural History, subsequently identified shocked quartz - considered strong evidence of an extra-terrestrial impact - in samples of sub-shale breccia from within the crater."[13]

"The recent geophysical surveys include an airborne electromagnetic system, which is sensitive to how well rocks conduct electricity, and airborne gravity gradiometry, which measures subtle changes in rock density. The surveys both confirm the earlier work and provide a new view of the Decorah Impact Structure. Models of the electromagnetic data show a crater filled with electrically conductive shale and the underlying breccia, which is rock composed of broken fragments of rock cemented together by a fine-grained matrix."[13]

"The shale is an ideal target and provides the electrical contrast that allows us to clearly image the geometry and internal structure of the crater," Bedrosian said.[13]


Main source: Earth
This is an aerial view of the Barringer Meteor Crater about 69 km east of Flagstaff, Arizona USA. Credit: D. Roddy, U.S. Geological Survey (USGS).

In the image at left is an aerial view of the Barringer Meteor Crater about 69 km east of Flagstaff, Arizona USA. Although similar to the aerial view of the Soudan crater, the Barringer Meteor Crater appears angular at the farthest ends rather than round.


Main sources: Astronomy/Balloons and Balloons
A research balloon is readied for launch. Credit: NASA.

Balloons provide a long-duration platform to study any atmosphere, the universe, the Sun, and the near-Earth and space environment above as much as 99.7 % of the Earth's atmosphere. Unlike a rocket where data are collected during a brief few minutes, balloons are able to stay aloft for much longer. Balloons for astronomy offer a low-cost, quick-response method for conducting scientific investigations. They are mobile, meaning they can be launched where the scientist needs to conduct the experiment, in as little as six months.

Infrared telescopes[edit]

The image is centered on SOFIA with its telescope doors open in flight. Credit: NASA/Carla Thomas.
The diagram names the mirrors of the SOFIA telescope. Credit: Eddie Zavala (NASA Armstrong) and Erick Young (NASA Ames).
The NASA logo is reflected in SOFIAs 2.5-meter primary mirror. Credit: NASA/Tom Tschida.

"SOFIA’s primary mirror, located near the bottom of the telescope, is 2.7 meters (almost 9 feet) across. The front surface, which is highly polished and then coated with Aluminum to ensure maximum reflectivity, is deeply concave (dished inward). Incoming light rays bounce off the curved surface and are all deflected inward at the same time they are reflected back up toward the front of the telescope."[14]

"Before the light reaches the telescope’s front end, however, it is intercepted by a small secondary mirror (about .4 meters across), which sends the light back down toward the center of the main mirror. About a meter above the center of the main mirror, a third mirror sends the light out through the side of the telescope, down a long tube which projects through the main aircraft bulkhead into the interior of the SOFIA aircraft. There, at the telescope’s focal point, the light will be recorded and analyzed by one of several different instruments."[14]

"Astronomers tend to compare telescopes based on the diameter of their primary mirrors. SOFIA’s telescope is usually referred to as a 2.5-meter meter telescope, rather than 2.7 meters, because the optical design requires that only about 90% of the mirror’s reflecting surface (called the "effective aperture") can be used at any one time. Although SOFIA’s telescope is by far the largest ever to be placed in an aircraft, compared to normal ground-based research observatories it is only medium-sized (the world’s largest single-mirror telescope, the Subaru, is 8.2 meters across)."[14]


Main source: Hypotheses
  1. Extremely high altitude powered flight may allow observation at a lower cost than a satellite.

See also[edit]


  1. DoD News Briefing, February 15, 1996 1:30 pm EST (from a [United States Department of Defense] DoD news briefing. Accessed 2008-06-21.)
  2. Francoise Micheau (1996). The Scientific Institutions in the Medieval Near East, In:. pp. 992–3. 
  3. Oliver J. Lee (1936). "Looking for Leonids from an airplane". Popular Astronomy 44: 23. Retrieved 2017-08-14. 
  4. 4.0 4.1 Oscar E. Monnig (February 1940). "Meteors and Meteorites: A meteor train photographed from an airplane". Popular Astronomy 48 (02): 93. Retrieved 2017-08-14. 
  5. 5.0 5.1 5.2 Lua error in Module:Citation/CS1 at line 3556: bad argument #1 to 'pairs' (table expected, got nil).
  6. 6.0 6.1 Lua error in Module:Citation/CS1 at line 3556: bad argument #1 to 'pairs' (table expected, got nil).
  7. J. Iwai, T. Ogata, I. Ohta, Y. Takahashi, T. Yanagita (1979). Saburo Miyake, ed. Primary Spectrum in the Energy Range of 1 Tev - 10,000 Tev Deduced from the Emulsion Chamber Experiment on the Airplane, In: 16th International Cosmic Ray Conference. 8. University of Tokyo, 3-2-1, Midori-cho Tanashi, Tokyo 18 JAPAN: Institute for Cosmic Ray Research. pp. 1–6. Bibcode:1979ICRC....8....1I. Retrieved 2017-08-14. 
  8. M. Merker, E. S. Light, R. B. Mendell and S. A. Korff (1970). A. Somogyi, ed. The flux of fast neutrons in the atmosphere. 1. The effect of solar modulation of galactic cosmic rays, In: Solar Cosmic Rays, Modulation of Galactic Radiation, Magnetospheric and Atmospheric Effects. 2. Budapest: International Conference on Cosmic Rays. p. 739. Bibcode:1970ICRC....2..739M. Retrieved 2017-08-15. 
  9. 9.0 9.1 9.2 Figueiredo N, Villela T, Jayanthi UB, Wuensche CA, Neri JACF, Cesta RC (1990). "Gamma-ray observations of SN1987A". Rev Mex Astron Astrofis. 21: 459–62. 
  10. Terrence J. O'Neill, Alan D. Kerrick, Farid Ait-Ouamer, O. Tumay Tumer, Allen D. Zych, R. Stephen White (April 28, 1989). "Observations of nuclear reactors on satellites with a balloon-borne gamma-ray telescope". Science 244 (4903): 451-4. doi:10.1126/science.244.4903.451. Retrieved 2012-06-10. 
  11. 11.0 11.1 Alfred Krabbe (March, 2007). SOFIA telescope, In: ‘’Proceedings of SPIE: Astronomical Telescopes and Instrumentation’’ (PDF). Munich, Germany: SPIE — The International Society for Optical Engineering. pp. 276–281. arXiv:astro-ph/0004253Freely accessible.  Check date values in: |date= (help)
  12. US Geological Survey. Iowa Meteorite Crater Confirmed. Retrieved 7 March 2013. 
  13. 13.0 13.1 13.2 13.3 13.4 13.5 13.6 Lua error in Module:Citation/CS1 at line 3556: bad argument #1 to 'pairs' (table expected, got nil).
  14. 14.0 14.1 14.2 Eddie Zavala and Erick Young. SOFIA Telescope. USRA. Retrieved 2016-02-06. 

External links[edit]

{{Astronomy resources}}{{Flight resources}}