SAS-2 Photon Events Catalog: 13,056 Gamma-Ray Photons from 28 Observations

13,056 photons detected by the SAS-2 satellite across 28 observation intervals. The catalog was created by NASA HEASARC, combining photon event data with exposure information from original OALT tapes into 28 FITS format image files. Each photon's right ascension and declination were converted to pixel coordinates using Aitoff projections on 512 x 512 pixel images.

Use Cases

• Map gamma-ray photon distributions across the sky based on the RA and DEC coordinates mentioned in the description.
• Analyze satellite observation intervals and exposures based on the combined OALT and event data.
• Reprocess or visualize raw photon event data using the FITS format and tools like XIMAGE or FPLOT mentioned in the description.

Strengths

• Contains 13,056 individual photon events for analysis.
• Data is consolidated from two original sources (Event Encyclopedia and OALT tapes) into a standardized FITS format.
• Provides 28 distinct observation intervals with target names and sky coordinates.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is known, but the specific features and data types within the FITS extensions are not detailed.

Provenance

Source

National Aeronautics and Space Administration (NASA), specifically the HEASARC.

Collection Method

Photon information from the Event Encyclopedia combined with exposure data from original 'Orbit Attitude Live Time' (OALT) tapes, processed into FITS images.

Time Range

Temporal coverage of the 28 SAS-2 observation intervals is not specified.

Freshness

Last updated 2026-03-13 19:06:25.082316; freshness should be verified.

Geography

Spatial coverage is celestial, based on sky coordinates (RA and DEC).