I. Release Working Table Selection
Release Working Point and Extended Source Databases have been drawn from
all scans meeting the
release tile selection criteria.
The Release Working Tables consist of all sources in the selected
scans that meet the following criteria:
| Requirement | Explanation |
| 1. Edge-Boundary Limits | Source must lie >10.0 arcsec (point sources) OR >15.0 arcsec (extended sources) from any 3-band tile edge |
| 2. Mag. and SNR Limits | Scan SNR
>7 AND Measurement SNR>7 (at least one band) for Point and
Extended Sources AND (J<15.1 OR Ks<13.5) for Extended sources |
| 3. Ptsrc - chi-squared limit | chi-squared < 10 (in at least one band), to select against cosmic rays and meteor trails |
| 4. Ptsrc - N/M | M > 3 AND N/M < 0.4 (in at least one band); N=No. frames on which source has >3-sigma detection, M=No. frames on which source could have been detected |
| 5. Not an artifact | No sources identified as an artifact in MAPCOR scan processing |
The SQL statements used to draw the Point and Extended Source Release
Working Tables from the Ops Database are given here:
For the Spring 99 release, these source selection rules were applied during the final step of catalog preparation. Becuase of the large size of the Second Incremental release, these filters were applied at the Working Release table generation stage to cut down the tables' sizes for the purpose of speeding up the final product processing tasks.
The Release Working Tables can be accessed via the IRSA Catalog Search service. The Working Point Source Table contains 192,446,578 records, and the Release Working Extended Source Table contains 1,020,058 records.
II. Final Product Generation Tasks
A number of production tasks must be performed with the Release Working Tables before the final Catalogs can be drawn. These tasks, listed below, include identification of artifacts in the source lists due to very bright stars and meteor trails, resolution of sources in scan overlap regions, extended source candidate classification, and point source position uncertainty updates. All of these tasks result in updates or additional DB fields that will be applied to the Release Working table records. The draw of the final Catalogs will be based on filters applied to the updated fields.
1. Source Handling in Tile Overlap Regions
2. Very Bright Star and Off-Scan Bright Star artifact detection and marking - DB_MAPCOR
3. Point Source Position Uncertainty Updates
4. Extended Source Classification
- E_Score > 1.4 OR G_Score > 1.4
- Additional extended source selection criteria
5. Meteor Trail Identification
6. Minor Planet Flagging
7. Extended Source Contamination Flagging in PSC
III. Catalog Fields
1. Ptsrcs Same as Spring 99 Catalog 2. Extsrc Same as Spring 99 Catalog 3. Extsrc "Shortform" Same as Spring 99 Catalog (in preparation) 4. Photometric Uncertainties Same as Spring 99 Catalog 5. Astrometric Uncertainties Same as Spring 99 Catalog
R. Cutri - IPAC
Last Update - 6 October 1999 17:00