Date: Wed, 29 Oct 1997 09:57:18 -0800 (PST)
Subject: 2MASS WG Mtg #135 Minutes

           IPAC 2MASS Working Group Meeting #135 Minutes

Attendees: R. Beck, T. Chester, R. Cutri, T. Evans, D. Engler,
           J. Fowler, L. Fullmer, T. Jarrett, D. Kirkpatrick,
           G. Kopan, B. Wheaton, S. Wheelock, J. White


1.) Southern-Camera Lab Data Analysis
2.) Northern-Camera Readout Time Test
3.) Lien and Action Item Review


1.) Southern-Camera Lab Data Analysis

    R. Cutri reported that the first run of the southern-camera
lab data through the DARKS subsystem resulted in most of the J
pixels being turned off in the mask because of the effects of a
light leak. The thresholds on trimmed-average standard deviation
were doubled, and most of the pixels then survived. G. Kopan
coadded the masks to determine the depth of coverage that would
be achieved with the masks produced by DARKS, and coverage looks
acceptable in J and H, but K is marginal. One decision to be made
in the near term is whether to replace the K array, which was
already known to be questionable.
    A hot-pixel test will be run next; this will involve editing
the scan parameter information to make one of the dark sequences
look like a survey scan to the pipeline, so that FREXAS will
perform source extraction and hot-pixel tests. This should give
some advance warning of any hot-pixel problems that might exist.

2.) Northern-Camera Readout Time Test

    R. Cutri reported that the data tape received today from the
northern observatory contains a special calibration scan set (six
scans/set) that employs a different array readout mode known as
"base-5" (normal mode is "base-6"). This mode reads the array out
faster and matches what the southern camera is designed to do. In
order to determine whether any significant effects are created,
the same calibration field was observed in both modes by the
northern telescope. The two variations must both use the standard
darks and responsivities, since no darks or flats were taken in
the "base-5" mode. Close inspection and comparison of the two
sets of results are requested.

3.) Lien and Action Item Review

    Most of the meeting was devoted to a review of the
outstanding liens and action items. A prioritized list is needed
for the upcoming Science Team meeting next week, and acceptance
criteria for the 2MAPPS version 2.0 delivery need to be
clarified. The detailed discussion will not be reported here, but
the most pressing items involved PSF modelling and parameter
tuning. An updated list of liens and action items is expected to
be issued after the Science Team meeting.