Date: Thu, 10 Dec 1998 16:10:28 -0800 (PST)
To: 2mass-staff
Subject: IPAC 2MASS WG Meeting #175 Minutes
Cc: chas, stiening, bgreen,
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           IPAC 2MASS Working Group Meeting #175 Minutes

Attendees: R. Cutri, S. Van Dyk, T. Jarrett, D. Kirkpatrick, R. Hurt,
           R. Tam, S. Wheelock, T. Evans, H. McCallon, D. Engler, 
           B. Nelson, J. Fowler, J. White, J. Rho, G. Kopan, W. Wheaton,
           J. Mazzarella, T. Chester


1.) General Project News

2.) IRSA

3.) AAS Meeting in Austin

4.) New and Standing Action Items


1.) General Project News

     The Science Team Meeting will be Monday and Tuesday, Dec 7 and 8.  An
Extended Source Workshop will be held on Monday from 9 AM to 12 PM, with the
regular meeting starting at 1:30.  On Tuesday the meeting will start at 8 AM.
The big items that will be discussed are the results of the Extended Source
Workshop, the Spring data release, and 2MAPPS 3.0.

     A reminder that the monthly progress reports are due tomorrow, Dec 2.

     No electronics changes have occurred in the north.
     The last 20 out of 23 days in the south have been perfectly clear.
     The big issue is whether or not to replace the H-band array in the north.
Do we, and when?  The replacement array appears to be reliable.  Additionally,
there is a cryo vacuum leak in the old array.  Replacing the array, however,
means that time will be taken away from preparing for the Spring release and
could set it forward.  A question is, how bad does the hole (2-3 coadd pixels
per panel) affect extended source (i.e., galaxy) photometry?

     December might be a good time to do the replacement, since the weather is
somewhat ratty at Mt. Hopkins.  But, this would require doing the subsequent
analysis over the holidays, which is not a lovely thought.

[Note added in proof:  The decision has been made to NOT change the H array,
unless significant further degradation.  This will be consider again during
the Summer 1999 shutdown period.]

     Another quirky problem has appeared, and is being called the "Nelson
effect."  On 980509n, there appears to be a cal scan problem, in that the second
cal scan, scan 112, in the cal block appears to be anomalously brighter by 0.2
mag in J, although the images look fine.  Yet another quirk for the QA people
to keep an eye out for.

[Note added in proof:  Shortly thereafter, this effect was found to be due to 
aberrant aperture photometry being used for the individual calibration scan 
calibration.  It does not affect the calibration derived for the night.  Steps 
are being taken to correct this for the calibration of the cal scan data.]

     J. Fowler introduced the issue of canonicals for late March, early April in
the north.  There are no new canonicals for this period, as the flats and darks
were changing rapidly.  This time span would amount to its own ~4- or so-day 
hardware period.  The failed responsivities are >~ 5% over canonicals.  So far, 
the problem has been detected by QA in 980403n, 980404n, and also 980405n.  
The problem could be corrected by possibly opening up thresholds and reprocess 
these nights.  It is not a global problem, since only 6 nights need to be 

     J. Fowler also indicated that the new K-band mask will be ready for nights
including and since 981118n.

2.) IRSA

     Discussion ensued about modifications to the current IRSA tools and 
monitoring of the IRSA site.  R. Cutri asked of J. Mazzarella whether the IRSA 
sites "irsa" and "irsatest" were or could be logged, to keep track of queries to
the system.  H. McCallon asked about being able to query on four corners of a 
sky region.  R. Cutri desires a simple query, based on giving a central RA and 
Dec and a search radius.

3.) AAS Meeting in Austin
     A tally was taken of all 2MASS team members who are either presenting or
interested in attending the AAS Meeting in Austin in January.  This list 
included R. Cutri, R. Hurt, B. Nelson, J. Mazzarella, D. Kirkpatrick, J. Rho,
and S. Van Dyk.  (J. Mazzarella will be manning the IRSA Exhibit at the 
meeting.)  Also interested in attending are W. Wheaton and T. Evans.  All were
reminded that the deadline for early registration and hotel reservations is
Dec 4 (Friday).

     S. Van Dyk is to approach the Science Team to see how many members will be
attending the meeting and would be willing to participate in manning the 2MASS

4.) New and Standing Action Items

%                                                      %
%                 ACTION ITEMS                         %
%                                                      %

      Action Item for all team members:  all are encouraged to attend the
Science Team meeting.

(Standing Action Items:)

a) Team members should continue testing the IRSA tools and the Sampler release.

b) Team members should continue to analyze data for Spring data release.