Infrared Astronomical Satellite, IRAS

Product Name
Chopped Photometric Channel Survey


The CPC instrument on IRAS was used to make maps at 50 and 100 microns by scanning its 1.2' diameter field of view in raster fashion. Typical maps are 40 x 40 pixels on a 20" grid. Each observation lasted about 4 to 7 minutes. Unfortunately, the CPC detectors were much less sensitive than expected and were plagued by signal-dependent spiking. Deglitching was included among the data reduction steps, but the correction made for responsivity variation was considered unsatisfactory by the instrument team and the resulting data are of lower quality than originally expected. Of the 2100 observations made with the CPC, 1500 were considered acceptable for publication. The instrument and data processing are described, and important caveats and an index of observations are given in the IRAS-DAX Chopped Photometric Channel Explanatory Supplement. Reduced observations are called CLEAN images; RAW images, uncorrected for glitches and the effects of responsivity variation, are available for comparison. In each case the 50 and 100 micron images are given in a single FITS file, one for the CLEAN image and another for the RAW image.

The survey is provided as a single tar file. When unpacked the individual files have names like CPC_0012S39_830601_062902.RAW. After the 'CPC_' the next four digits give the Right Ascension of the first pixel; 'N' or 'S' indicates the celestial hemisphere; the next two digits give the declination; after '_' the next six digits give the date of observation in the form yymmdd; 'RAW' indicates uncorrected data, 'CLEAN' reduced data."

IRAS-DAX Chopped Photometric Channel Explanatory Supplement, prepared by P. R. Wesselius, D. A. Beintema, A. R. W. de Jonge, T. A. Jurriens, D. J. M. Kester, J. E. van Weerden, J. de Vries, and M. Perault (Groningen: SRON).

Version and release date: 1.0, 1986 Jan

Chopped Photometric Channel Field, Data Download:  CPC.TAR

Sample FITS header

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