Date: Wed, 14 Jan 1998 17:35:40 -0800 (PST)
Subject: 2MASS WG Mtg #140 Minutes

           IPAC 2MASS Working Group Meeting #140 Minutes

Attendees: R. Beck, T. Chester, R. Cutri, T. Evans, J. Fowler,
           L. Fullmer, J. Huchra, T. Jarrett, D. Kirkpatrick,
           G. Kopan, B. Light, J. Mazzarella, H. McCallon,
           B. Nelson, S. Schneider, B. Wheaton, S. Wheelock,
           J. White


1.) Camera Status
2.) Camera Timeouts
3.) 2MAPPS Redelivery Schedule
4.) Cal Scan Reruns
5.) Optical Catalog Association Status
6.) Database Status
7.) 2MASS at the AAS


1.) Camera Status

    R. Cutri reported that the J bias jumps have resumed in the
northern camera. This camera recently warmed up by accident, but
it is not known whether this is connected to the return of the
bias jumps. The southern camera is undergoing lab tests and is
expected to be shipped to Chile in about a week. Data from the
southern observatory are anticipated about mid-February.

2.) Camera Timeouts

    Ever since the survey began, timeouts in the camera have been
observed on about 10% of the scans. The origin of this problem is
not known. The symptoms are a breakdown in communication between
the data raptor (frame grabber) board in the camera electronics 
and the instrument control computer, after which data taking
halts. The operators must then manually reset the system and
restart the affected scan. This has reduced survey efficiency by
about 10%, and an improvement of this situation is desired.
    If possible, the cause of the timeouts will be identified and
fixed. Since the search for this cause has so far proved
fruitless, some fallback position is needed. This will take the
form of modifying the observing control apparatus to recognize
that a timeout has occurred and resume the scan with a frame
missing; this frame will be dummied somewhere in the data
preparation stage, i.e., a frame full of NaNs will appear to the
downstream 2MAPPS software. In the near term, 2MAPPS will
identify scans that have missing frames using information
provided by the observatory in the scan header information, and
will not attempt to process it.  Eventually, 2MAPPS will be
modified to process the scan despite the dummied frame, and the
missing information will simply produce a local drop in signal-
to-noise ratio. The modified 2MAPPS is expected to be version 2.2
and to be delivered in the summer (version 2.1 will be the
southern-tuned version).
    Even the near-term changes will require RDFRAME to be
redelivered, and the changes therein will depend on what changes
the observatory can support in the way of providing information
about which frame was skipped. The redelivery of RDFRAME is
therefore not going to be coordinated with the 2.N redeliveries
of 2MAPPS, but will be inserted as feasible. When this is done,
the implementation of the soft-saturation-image capability will
also be accomplished, since this has already been done in RDFRAME
and needs only minor modifications to DARKS and DFLAT to be
completed (if the real soft-saturation images are not available
when this redelivery occurs, temporary images filled with the
current all-pixel values will be generated and used in the

3.) 2MAPPS Redelivery Schedule

    R. Cutri listed the expected upcoming 2MAPPS versions, their
capabilities, and delivery dates. Version 2.0 is due February 2
and is intended to be able to process the northern data without
further changes until data acquisition ends. Version 2.1 will be
capable of processing both hemispheres, and so it will reflect
tuning changes and possible software updates for the southern
telescope; its delivery date is rather uncertain but expected to
be about May 1. Version 2.2 will incorporate the camera-timeout
dummy-frame capability discussed in section 2 above, and is
expected some time in the summer (if the timeout problem can be
solved in the hardware in the near future, this version will not
be produced).
    The expected timeline for version 2.0 is as follows. After
the February 2 delivery, system integration will be done, ending
on February 15. From February 16 to March 1, system testing with
a new RTB will take place. The decision to assemble a new set of
data for regression testing is based on the known shortcomings of
many scans included in the old RTB, i.e., we are not interested
in comparing new and old processing of those scans. Anyone with
suggestions for what should be included in the new RTB should
send them to Roc. In addition to plenty of nominal data at
various source densities, scans with bright stars, seeing
variations, and bias jumps were recommended for inclusion.
    On March 2, a science team meeting will be held to discuss
the RTB results and decide whether to accept version 2.0 of
2MAPPS. The acceptance criteria include requiring a complete
end-to-end system (with full database access capability) and
satisfaction of all relevant Level 1 requirements (i.e., not
global-uniformity requirements, which cannot be evaluated at that
time). If all goes well, northern-observatory production will
begin on March 3. Testing and tuning for southern-observatory
data will begin around February 16 and result in 2MAPPS version
2.1 about May 1, plus or minus a few weeks.
    R. Cutri requested that all cognizant engineers whose
subsystems have science-team advisors send him and the advisors a
status report on the delivery work.

4.) Cal Scan Reruns

    R. Beck reported that reprocessing of all cal scans had been
completed. This includes cal scans between 970515 and 971224.
These were processed by the version of 2MAPPS that was online as
of December 19. These reprocessed cal data will be restored to
rodan's /o2 disks and will replace the versions currently online. 
Note that the survey scan data that were previously processed
will remain online.  Be aware that the cal and survey data will
have been processed with difference pipeline versions.

5.) Optical Catalog Association Status

    J. Fowler inquired about the status of the optical-catalog
association requirements, which were pending some offline
investigations of the needs of the rare-objects group and some
Monte Carlo testing of false-association rates. R. Cutri reported
that unless there is a change of recommendation by the rare
object team, the optical association will include a third pass to
identify possible proper motion matches. J. Fowler reported that
the likelihood of including any changes in POSPTS with the 2MAPPS
2.0 delivery was now quite small and quickly vanishing.

6.) Database Status

    J. Mazzarella reported that significant improvements in the
data base access setup had been achieved and that he would
distribute a memo discussing the status of this work and
instructions on how to exercise the current capabilities.

7.) 2MASS at the AAS

    R. Cutri reported that the 2MASS exhibit booth at the
Washington AAS meeting was very well recieved. Especially
impressive was the very large 3-color montage image that was
prepared by Gene Kopan. "Good work" to one and all.