These data products are time-ordered versions of the entire IRAS sky
survey and were created to aid modeling and extracting the zodiacal emission
intensity in the various extended source data products. The databases retain
the subdivision of the original survey into semi-daily Satellite Operation
Programs (SOPs) and individual continuous survey scan observations (OBS).
Two versions of the Zodial Observation History File (ZOHF) exist:
- Standard ZOHF
A low-resolution version of the entire IRAS sky survey. The average
of all detectors within a band produced a 0.5° wide fan beam which
was then boxcar averaged for eight seconds to produce a 30' x 32' beam.
Pointing information was similarly averaged over eight seconds to accompany
the infrared data.
- 2' Resolution ZOHF
An intermediate-resolution (2' in-scan x 30' cross-scan) version of
the entire IRAS sky survey. The time averaging interval is one-half second
rather than the eight seconds of the standard ZOHF.
Infrared Astronomical Satellite (IRAS) Catalogs
and Atlases, vol. 1, Explanatory Supplement, 1988, ed. C. Beichman, et
al., NASA RP-1190 (Washington, DC: GPO)
Version and release date: 30' 3.1, 1990 May; 2' 1.0, 1990 May.