Photometric Zeropoints for the KPNO IRIM Observations
of the Hubble Deep Field
Most of the time spent observing the HDF with IRIM was photometric.
However, a few intervals were not perfectly clear, although usable data
was obtained nevertheless. For the version 1 release, we have set the
zeropoints for the "grand sum" images by bootstrapping from subsets
of the data taken at low airmass and during photometric conditions
as established by standard star observations. For version 2, we plan
more extensive checks of the photometric calibration, but we believe
that the version 1 calibration should be good to 5%.
The zeropoints below are given in the sense that
mag = zeropoint - 2.5 log N
where N is the number of counts measured for the object of interest
in the HDF/IRIM v1 release images. Airmass corrections have already
been incorporated.
The zeropoints are:
| Bandpass
| Limiting Magnitude
|
| J |
25.25 |
| H |
25.16 |
| K |
24.57 |
Return to the HDF/IRIM home page
Mark Dickinson: med@stsci.edu 10/24/96