COBE DIRBE Products

DIRBE Calibrated Annual File (DCAF) and DCAF Pixel Index

Consider using the DIRBE Sky and Zodi Atlas instead. The DCAF files contain the same data as the Weekly Sky Maps but are organized differently. This product gives a pixel-by-pixel view of the intensity variations seen as a function of time, collecting all the weekly-averaged intensities measured at a given pixel into a single file. Those who wish to study or model time-variable signals, such as the zodiacal light, will find this organization convenient. There are 6 DCAF data files, one for each face of the COBE Sky Cube, and each data file is accompanied by a DCAF Pixel Index file, which is designed to facilitate data retrieval. The files are FITS binary tables. A typical DCAF data file is ~200 MB in size. To order the DCAF data on CDs, contact the Request Coordination Office. The DCAF files are on line.

The DIRBE measures linear polarization in ecliptic coordinates, with positive position angles measured east of the local line of longitude. Linear polarization is described by the Stokes parameters Q and U, which are related to the degree of polarization, P, and the position angle, alpha, of the sky polarization vector via Q = P cos(2 alpha) and U = P sin(2 alpha).