II. Contents of the First 2MASS Incremental Data Release
1. General Properties of the Data Release
- Range of Dates From Which Release Was Drawn: 1997 June 7 - 1998 January 30 UT
- Total Number of Fully or Partially Photometric Nights in that Range: 100
- Number of Tiles Included in Release: 3391
- Area of Release (includes a 10´´ inner border for each tile): 2483 sq.degrees
- Map of Regions Included in Release
(galactic aitoff projection with equatorial coordinate grid, overlaid on 100 micron IRAS all-sky map) - Range of Galactic Latitudes Covered (not complete): -51.0° < b < +86.7°
- Criteria for Selection of Tiles to Include in Release:
- Data Acquired in Photometric Conditions
(photometric zero point offsets < 0.04 mag in all 3 bands) - Photometric Sensitivity Meets Level 1 Requirements in all 3 Bands
(based on Average Sky Background Levels and Seeing in Tile) - Average Seeing FWHM < 3.5´´ in all 3 Bands
(for accurate photometry and star/galaxy separation) - H-Band Atlas Image Background Residuals Due to Airglow < 1.20 DN
(for accurate extended source photometry) - Tile Must Fall in Contiguous Block of >3 Acceptable Tiles
(for accurate assessemnt of astrometric residuals)
- Data Acquired in Photometric Conditions
- Basic Tile Information Available in the
Scan Information Table Accessible
via IRSA/CATSCAN
- UT Observation Date and Time
- Reconstructed Tile Corner Positions
- Mean Photometric Parameters
- Mean Point Source Noise Levels
- Mean Extracted Source Densities
[Last Updated: 1999 May 6; by R. Cutri]
Previous page. Next page.
Return to Explanatory Supplement TOC Page.