Date: Tue, 23 Sep 1997 18:14:56 -0700 (PDT) From: email@example.com To: firstname.lastname@example.org Cc: email@example.com, firstname.lastname@example.org, email@example.com Subject: 2MASS WG Mtg #130 Minutes IPAC 2MASS Working Group Meeting #130 Minutes 9/23/97 Attendees: R. Beck, R. Cutri, D. Engler, T. Evans, J. Fowler, L. Fullmer, T. Jarrett, D. Kirkpatrick, G. Kopan, B. Light, J. Mazzarella, H. McCallon, B. Nelson, J. White AGENDA 1.) 14-Bit Tests 2.) Data Compression 3.) QUALITY Subsystem Requirements 4.) Sample Data Base Loading 5.) Optical-Catalog Associations 6.) Calibration Strategy Change DISCUSSION 1.) 14-Bit Tests R. Cutri reported that a test is underway in which the raw data are simulated as 14-bit values by masking off the two least significant bits in the pixel values of all frame data. The purpose of this test is to judge the impact of going to 14-bit A/D converters in the camera electronics. This option is being considered as a solution to the problems encountered with the current electronics in the cameras for both hemispheres (although it is possible that just the A/D converter for J band in the northern-hemisphere will be replaced, in this case with a 16-bit A/D converter; this would be expected to solve the J-band single-quadrant bias-jump problem). J. Fowler reported that the standard deviations about the dark trimmed averages increased by about 0.12 DN for the Read1 darks and by about 0.33 DN for the Read2-Read1 darks. G. Kopan reported that early checks of the flattened-frame noise showed increases similar in size, possibly a bit smaller. R. Cutri requested all team members to investigate differences in the products once the test run finishes, which should be this evening (9/23/97). The old results are in o2/TEST/970608n, and the new results are in /o1/TEST/970608n. 2.) Data Compression R. Beck reported that the newly installed compression scheme was getting five nights' data on a single tape. These were summer nights, typically 14 GB each. It was noted that the previous estimate of three nights per tape was based on longer nights. This should tend to offset the recent $10 price increase of DLT tapes. R. Cutri reported that the combination of the IPAC precompensation and DLT hardware compression has been tested at UMASS and will likely be installed at Observatory soon. 3.) QUALITY Subsystem Requirements The requirements for the QUALITY Subsystem have been continuing to accumulate as new failure modes are found. The current system is working well, but additional capabilities are being designed and implemented to aid in interpreting the numbers displayed, and interface discrepancies are being worked out. C. Beichman has requested an updated requirements document and schedule for version 1.0 of this capability. R. Cutri, L. Fullmer, and D. Kirkpatrick will collaborate on this task. 4.) Sample Data Base Loading T. Evans reported that problems have arisen in the database loading activity that is being performed to support the sample database composed of the results from eleven selected observation nights. Some fields appear to overflow occasionally in some input files, and other files appear to be missing. The former problem has been encountered with some extended-source files, and the latter with some calibration files. T. Evans will work with T. Jarrett and S. Wheelock to resolve these discrepancies. The error information provided by Informix leaves much to be desired, as it does not indicate which field it finds unacceptable, and not always which line of input data. 5.) Optical-Catalog Associations R. Beck requested information on the schedule for the upcoming coordinated redeliveries of POSPTS, GALWORKS, and CALMON in support of the optical-catalog associations. Adding the association fields to the output of POSPTS has caused changes in several software interfaces, necessitating the coordination in redeliveries (DBMAN is also involved, but will not attempt to operate on the new data until some future time after the eleven-night sample database has been successfully set up). Since the 14-bit test is still running, and since one additional diagnostic capability has been added to the POSPTS design, it was decided to wait until Thursday to perform the redeliveries. It should be noted that this version of POSPTS will include the final position-refinement capability, which H. McCallon was able to code and test sooner than expected. Tests showed that the final positions differed from the POSFRM solution by about 0.1 arcsec in the scan direction and by about 0.05 arcsec in the cross-scan direction. 6.) Calibration Strategy Change R. Cutri reported that the calibration strategy has been changed from requiring two calibration observations every two hours to one every hour. A calibration observation consists of six calibration scans. This will permit better time resolution of calibration changes, resulting in smaller blocks of data having to be rejected due to failure of the requirement to be bracketed by three acceptable calibration scans.