Infrared Astronomical Satellite
| IRAS | |
|---|---|
|
|
| Type: | Space telescope |
| Country: |
 United States / Netherlands / United Kingdom 
|
| Operator: |
NASA / NIVR / SERC |
| COSPAR-ID : | 1983-004A |
| Mission dates | |
| Dimensions: | 1073 kg |
| Begin: | January 26, 1983, 02:17 UTC |
| Starting place: | Vandenberg SLC-2W |
| Launcher: | Delta 3910 650 / D166 |
| Status: | in orbit |
| Orbit data | |
| Rotation time : | 102.9 min |
| Orbit inclination : | 99 ° |
| Apogee height : | 903 km |
| Perigee height : | 885 km |
The Infrared Astronomical Satellite ( IRAS ; Dutch Infra-Rood Astronomische Satelliet ; German infrared astronomical satellite ), launched in 1983, was the first space telescope for the middle and far infrared . With its help, the IRAS Catalog of Point Sources , Version 2.0 was created.
IRAS was developed jointly by the USA , Great Britain and the Netherlands . The IRAS telescope was a Ritchey-Chrétien-Cassegrain telescope with a beryllium primary mirror 60 cm in diameter. The focal length was 5.5 m, f / 9.6 and the aperture 0.57 m. To suppress its own heat radiation, the mirrors and the detector plate were cooled to a temperature of 2 to 5 Kelvin using liquid helium as a coolant .
The main instrument was an arrangement of 62 infrared detectors (survey array) , with which a complete survey of the sky at wavelengths of 12, 25, 60 and 100 µm with an angular resolution of a few arc minutes was obtained. Further instruments were a low-resolution infrared spectrometer for wavelengths from 8 to 23 µm ( Low Resolution Spectrometer , LRS ), with which about 5000 spectra were obtained, and a photometer for wavelengths 50 and 100 µm ( Chopped Photometric Channel , CPC ).
Mission history
IRAS was launched on January 25, 1983 and operated until the coolant was exhausted on November 21, 1983.
As a space observatory above the earth's atmosphere , IRAS was able to observe celestial objects even at wavelengths that can not be used from the earth due to the absorption of the atmosphere. IRAS was in a low polar near - polar sun-synchronous earth orbit, in which the satellite could constantly turn the back of the earth and a sun shield towards the sun to shield off disturbing thermal radiation. For this purpose, the telescope was guided across the sky in a steady movement along two long overlapping strips at a distance of 30 ° along ecliptic meridians, with the strip moving approximately 1 ° forward every day. 96% of the sky was covered with at least two scans and two thirds of the sky were scanned three times. Near the ecliptic poles, some areas were scanned four times. The individual observations were several months apart.
A rough model of the background radiation is included in the results. However, there are several sources of error in the star catalog that could not be completely eliminated. Objects that only appear in one of the two scans, i.e. that could not be confirmed in subsequent measurements, were not listed, but some of these objects have not been removed from the catalog. These include objects from the solar system that were not known at the time, comet tails and leftover debris and dust in comet orbits. In the case of very bright sources, the detectors were saturated and could no longer register any differences in brightness. The detectors tended to streak.
Results
blue = 12 micrometers,
green = 60 micrometers,
red = 100 micrometers.
Objects shown in blue and white are warmer, red ones are colder. The ribbon in the middle is the Milky Way .
The IRAS mission was an important milestone in infrared astronomy . The sky survey and the catalog of over 300,000 sources obtained from it are still important aids in astronomy twenty years later. Key discoveries include:
- Comets and the streaks of dust they leave behind
- Dust discs around nearby stars such as B. Wega
- Young stars that are still embedded in the clouds of gas and dust from which they were formed
- Infrared cirrus : The filamentous ' cirrus ' structure of cold dust in the interstellar medium of the Milky Way
- Infrared galaxies , which radiate the high luminosity generated by many young stars almost exclusively in the far infrared
- Experience with IRAS was taken into account in subsequent infrared missions, such as the Infrared Space Observatory from the 1990s and the Spitzer Space Telescope , which was launched in 2003, as well as for the NICMOS instrument of the Hubble space telescope.
See also
Web links
- Introduction to IRAS (English)
Catalogs at VizieR
- IRAS catalog of Point Sources, Version 2.0 (IPAC 1986)
- IRAS Serendipitous Survey Catalog (IPAC 1986)
- IRAS Faint Source Catalog,
- IRAS Point Source Reject Catalog (IRAS 1989)
- IRAS Faint Source Reject Catalog (IPAC 1992)
- IRAS Low Resolution Spectra (IRAS team, 1987)
- IRAS Small Scale Structure Catalog, Ver 1.00 (Helou + 1986)
- Catalogued Galaxies + QSOs observed in IRAS Survey, Vers.2 (IPAC 1989)
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- ↑ Orbital data from Infrared Astronomical Satellite in the Encyclopedia Astronautica , accessed on August 16, 2012 (English).
- ↑ Detailed Description of II / 125. In: VizieR. Center de Données astronomiques de Strasbourg, January 29, 1994, accessed on July 27, 2008 .
- ^ Mission to Universe Infrared Astronomical Satellite. NASA / Jet Propulsion Labaratory, accessed January 28, 2020 .
- ^ ISSA Processing Notes. Retrieved July 2, 2017 .
- ^ Characteristics of the IRAS Data. Retrieved July 2, 2017 .