January 25 – IRAS

IRAS, the Infrared Astronomical Satellite was the first space-based observatory to perform a whole sky (almost: it covered 96%)  infrared survey.  It was launched on January 25th 1983 from Vandenberg Air Force Base, and was a joint US/UK/Netherlands project.  It identified over 350,000 new infrared sources, expanding the catalog by about 70%.

IRAS (image credit: NASA/JPL)

IRAS (image credit: NASA/JPL)

You can get an idea of just how big the survey was in the following image, looking across the plane of the Milky way, and showing a point for each infrared source.  You also get to see the fairly obvious bits it missed out.

IRAS Point Source Map (image credit: Infrared Processing and Analysis Center, Caltech/JPL. IPAC is NASA's Infrared Astrophysics Data Center).

IRAS Point Source Map (image credit: Infrared Processing and Analysis Center, Caltech/JPL. IPAC is NASA’s Infrared Astrophysics Data Center).

The blue points in the image are stars, yellowy-green patches are galaxies, and red is infrared cirrus, cloud-like structures of cool (about 25 Kelvin) galactic dust, identified for the first time by IRAS.

Somewhat surprisingly for an observatory dedicated to the discovery of fixed point sources, IRAS also gets a mention as a discoverer of three asteroids and six comets.  The asteroids are a Mercury-crossing Apollo called 3200 Phaethon, parent of the Geminid meteors; the main belt asteroid 3728 IRAS, and the unnamed (10714) 1983 QG, discovered August 31st 1983.


Also today, in 1967, we have the launch of Cosmos 139.


 

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