Date: Tue, 17 Nov 1998 16:27:00 -0800 (PST)
To: 2mass
Subject: IPAC 2MASS WG Meeting #172 Minutes
Cc: chas, stiening, bgreen,
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           IPAC 2MASS Working Group Meeting #172 Minutes

Attendees: R. Cutri, S. Van Dyk, T. Jarrett, D. Kirkpatrick, R. Hurt,
           R. Tam, W. Wheaton, S. Wheelock, T. Handley, T. Evans,
           H. McCallon, R. Beck, L. Fullmer, B. Nelson, J. Fowler,
           J. Rho, J. Gizis (visiting)


1.) Project Update

2.) 2MASS Sampler

3.) PSF Generation

4.) Tales from the Beaches of Mexico

5.) New and Standing Action Items 


     The meeting began with tasty and, fortunately, non-amoebic treats from

1.) Project Update

     J. Rho has started with 2MASS at IPAC.  Her duties include science
analysis for "preliminary data product generation."

     The northern R1 H-band exposures have a noisy column.  It has been a 
problem in Ks, and column 129 has been turned off in Ks R1 for some time. 
R. Cutri's suggestion is to do the same thing in the same way for H.  The 
drawback is that this may introduce a new hole in the coadd.  However, since
the camera rotation provides a two-pixel overlap, we may recover what's masked.
Most R1 sources will be in the Galactic Plane, which would provide a good test;
however, we have no requirements for the Plane.

     Dec 7 and 8 will be the next Science Team meeting here at IPAC.
     R. Cutri proposes to trim 5 arcsec from the interpolated edge of each scan
before the data go into the database, but inquired as to the ramifications of 
this procedure.  If the overlap is as it should be, a source detected in three
bands clipped off the edge of one tile should be on the next tile.  Some 
question arose about the errors introduced by connecting scan corners with great
circles to define the edges.  The concern was that a great circle along a scan
edge will bow out slightly with respect to the scan centerline.  H. McCallon
responded that the effect should be very small, but that he would verify it.
It turns out that for a six-degree scan the maximum outward bowing on each
side at scan center is about 0.35 asec [256*(1-cos 3)].  Compared to the 
errors introduced by the assumption that a scan can be defined by four corners
in the first place, this is very small.  Thus, he sees no problem with
continuing to use great circle boundaries to define which sources lie within the
four-corner points.  L. Fullmer will generate some overlap statistics to
analyze the problem further.

     This trimming is being used for the Sampler.  R. Tam has not found 
anything unusual in the Sampler as a result.  The general trimming would have
implications for the database and catalog generation, leading to possible
disconnects between the point source and extended source catalogs.  The trimming
would be done before MPCAT is run; MPCAT results will not be connected in the
first place.

2.) 2MASS Sampler

     R. Tam is hand-editing bright-star artifacts.  He was asked to deliver a
catalog of sources to be removed by tomorrow.  L. Fullmer had already done this
for the extended source catalog and would provide a list by tomorrow.  The
Sampler will now be on or around Nov 30.

     The CD-ROM for the AAS meeting can be generated with a 15-day turnaround
for $0.95 per unit.  The contents of the CD-ROM should be ready to be packaged
by Dec 1.

3.) PSF Generation
     W. Wheaton indicates that PSF generation is coming along pretty well.  He
is racing the clock, as both Dino and Barney are cranking away.  Barney will
leapfrog to 1998 June (a hardware breakpoint), as Dino will then leapfrog to 
Oct, the next hardware breakpoint.
4.) Tales from the Beaches of Mexico

     S. Van Dyk, in his groggy and green-at-the-gills state, described the
exposure 2MASS received at IAU Symposium 193, on the Wolf-Rayet phenomena in
massive stars and galaxies, held the previous week in Puerto Vallarta.  He,
along with T. Jarrett, had compiled photometry for several Wolf-Rayet stars and
galaxies that have been processed by the pipeline, and these results were
presented in a poster at the meeting.  Many participants were interested and
impressed with the 2MASS capabilities in this research area.  The beach was 
nice, too.  But, S. Van Dyk shouldn't have had that glass of limonada with ice
on the last day....

5.) New and Standing Action Items

%                                                      %
%                 ACTION ITEMS                         %
%                                                      %

      R. Cutri did not assign any new action items.  

(Standing Action Items:)

a) Team members should continue testing the IRSA tools.

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

c) Team members are reminded that performance reports covering October and 
November will be due on Dec 2.