Date: Thu, 22 Oct 1998 18:08:41 -0700 (PDT) To: 2mass Subject: IPAC 2MASS WG Meeting #169 Minutes Cc: chas, stiening, bgreen Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Content-MD5: h5JR0cG3DLuyJIYvY7Gf2A== IPAC 2MASS Working Group Meeting #169 Minutes 10/20/98 Attendees: R. Cutri, S. Van Dyk, R. Beck, T. Evans, R. Hurt, H. McCallon, S. Wheelock, R. Tam, W. Wheaton, T. Jarrett, T. Handley, D. Kirkpatrick AGENDA 1.) Project Update 2.) New and Standing Action Items DISCUSSION 1.) Project Update R. Cutri spent a night at Mt. Hopkins recently. He reported that the night consisted of a frenzy at dusk, a lull for the rest of the night (as the telescope automatically observes), and a renewed frenzy at dawn. It appears that a problem occurred with the previous night's data (981020n) in the north. A strange pattern appears in the images, indicating some problem with the camera electronics. This marks the end of the use of the old Gatir electronics. R. Stiening was headed to Mt. Hopkins to swap in the new Leach electronics. Data from the facility *are* relatively indistinguishable between old and new electronics, but, obviously, the data taken with the new electronics will have to be characterized. Some work will therefore be involved at IPAC. Everyone has submitted their `wish lists' for 2MAPPS 3.0. Also, WG members have submitted their performance reports, which will become a monthly occurrence. The `oddity of the week' appears to be hot pixels in the southern data. B. Nelson will be moved to a regular staff position soon and will serve as an additional QA scientist. That means that QA should become an additional 33% more efficient. However, this is balanced (precariously) against the fact that in a week, dino (aka SOB) will be going online, leading to 50% more processing efficiency. Dino will be loaded with 200 Gb of disk. Dino likely represents the last of the Enterprise 450's that will be purchased. Since the recent recollimation of the northern telescope, the standard second image moment ratio is no longer a sensitive diagnostic for image elongation in the J and H bands. A more sensitive diagnostic, developed by T. Jarrett, evaluates the true aspect ratio at the appropriate position angle of the elongation of the image. The new diagnostic will be reported in the standard qDATEh.psf.see file, and that file will have a slightly different format, with three extra columns for the position angles. This new routine must be tested further, but R. Cutri would like it implemented in the QA process by week's end. S. Wheelock would like to implement "PSFCOR", the routine to interpolate the photometric cross-scan bias correction across cal scans. R. Cutri had not yet had a chance to read her memo on the routine. T. Evans reported that the database came back up after the weekend's power outage. She is still validating the database load that took place over the weekend. However, it is clear that one of the southern database indices got corrupted. This could just be the result of a transient in the system. The server may have gotten into a weird state, so caveat emptor to all team members. The Sampler seems to be OK, but this had just gotten reloaded. She wants to reload the point source catalog for the Sampler. T. Evans and T. Handley reported that a recent reindexing of the database locked up OPS for 25 hours, which is too long. Only one-tenth of the sources observed are currently in the database (only two nights of southern data are currently in the database), which raises the horrific concern whether future database loads and indexing will take geometrically longer and forbidding amounts of time. Indexing is clearly needed for good queries to be accomplished, however, not if the indexing takes weeks to perform! H. McCallon produced a tome on the evaluating and updating of positional uncertainties. These documents have now been placed online at the 2MASS internal website. The issues remain whether old positions plus deltas are put into the source catalogs, or new positions are added to the catalogs, once the old positions are corrected. The positional uncertainties need to be updated for the spring data release. Team members are encouraged to peruse his memos online. W. Wheaton asked about information that can be obtained about when the cameras warm up and how this affects the detector saturation levels in the north. R. Cutri urged W. Wheaton to first get the saturation levels for the south and then possibly reanalyze the saturation levels for the north later. T. Jarrett asked about "J-banding", where J jumps are seen along half of the coadds in the south. He pointed out that these jumps could kill galaxy photometry in GALWORKS. The jumps could lead to 20%, or more, errors in the photometry. R. Tam will look at the amplitudes of the jumps and how many scans they affect. These could be bias jumps, similar to the "J quadrant dropouts" seen in the north. So, a precedent exists for this problem. The solution may be to have to throw out these data. Individual coadds must therefore be examined first. The problem has only been detected so far in the early southern nights that have been processed. R. Beck will process some sci scans in recent nights, and nights in between, so that it can be determined whether or not the problem has persisted since March/April. 2.) New and Standing Action Items %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % ACTION ITEMS % % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% R. Cutri did not assign any new action items. [However, in an e-mail since the WG meeting, he has set a deadline of Dec 2 for the performance reports covering October and November.] (Standing Action Items:) a) Team members should continue testing the IRSA tools. b) Team members should still contemplate the sci-staff structure proposals and voice their opinions. c) Team members should continue to analyze data for spring data release.