First Data Release - August 2001
NOTE: This page provides details specific to this data release. Please look at common ground for more information. ALL data will be reprocessed uniformly at the end of the survey.
First Release (August 2001)
| Subfield | Catalog | FITS Images | JPEG (from BVR) |
JPEG (from Rz) |
| F1p22 | F1p22.cat.gz | B, V, R, I, z' | F1p22BVR.jpg (~ 3.0 MB) |
F1p22Rz.jpg (~ 2.5 MB) |
| F4p22 | F4p22.cat.gz | B, V, R, z' | F4p22BVR.jpg (~ 3.0 MB) |
F4p22Rz.jpg (~ 2.5 MB) |
The catalogs are produced by SExtractor (version 2.1.6) using the parameter files default.sex and default.conv and the matched aperture method which consists of detecting objects in the R image (the deepest and sharpest), and evaluating on each of the four/five filters BVRz'/BVRIz'. If the object flux is within the sky noise SExtractor sets its magnitude to 99. More details about SExtractor can be found here.
On February 20, 2002,the first catalogs and images were updated to reflect more accurate photometric zeropoints and astrometry. Replacing any old versions you have downloaded is highly recommended.
The catalog for each subfield is contained in a gzipped ascii file, one object per line, with the following space-separated columns:
| Column Name | Meaning |
| Alpha | right ascension (2000.0) |
| Delta | declination (2000.0) |
| X | x intensity weighted centroid |
| Y | y intensity weighted centroid |
| A | semi-major axis |
| B | semi-minor axis |
| THETA | position angle |
| FLAGS | SExtractor flags Note: use objects with FLAGS != 0 at your own risk! In particular, do not use the total magnitudes of objects with flags including 1. |
| MAG_APER | aperture magnitude (diameter = 10 pixels ~ 2.57 arcsec) |
| MAGERR_APER | aperture magnitude error |
| MAG | total magnitude |
| MAGERR | total magnitude error |
| MAG_ISO | isophotal magnitude |
| MAGERR_ISO | isophotal magnitude error |
| ISOAREA | isophotal area |
Columns 1-8 always contain Alpha, Delta, X, Y, A, B, THETA and FLAGS. The remaining columns are listed once for each photometric band in the order BVRz' (BVRIz' for F1p22).
