IPAC 2MASS Working Group Meeting #82 Minutes

IPAC 2MASS Working Group Meeting #82 Minutes, 12/12/95

Attendees: R. Beck, C. Beichman, R. Cutri, T. Evans, J. Fowler, L. Fullmer, D. Kirkpatrick, G. Kopan, B. Light, C. Lonsdale, H. McCallon, S. Terebey, J. White


  1. Survey Strategy
  2. SIS Scrutiny
  3. Persistence Blanking in Images


  1. Survey Strategy -- The Survey Strategy Requirements Document has been taking shape under the care of C. Lonsdale, and several aspects that affect 2MAPPS were discussed.

  2. SIS Scrutiny -- As part of the preparation for the CDR on January 26, it is desired that the "key" SIS's be scrutinized to increase the probability that all of the right information to support the final products is flowing through the system. The "key" SIS's are primarily those which transmit the data of final scientific interest or impact them directly. Although putting the SIS's in immaculate form before the Christmas holidays is not considered a realistic goal, it is advisable for each cognizant engineer to begin a careful examination of the SIS's that are input and output by his/her subsystem, and if time permits, the other SIS's.

    One useful suggestion that came out of the SIS discussion was that a standard FDD coding requirement should be incorporated that requires each output table or FITS file header to contain a line indicating the version identification of the generating program and the processing date and time (J. Fowler may be contacted for information on obtaining the date/time information in Fortran). In the case of table files, the corresponding line from the program that generated an input table file should be carried over into any output table files, along with other header information (this is normally done anyway with FITS headers, where entire headers are copied from input to output, with "history" lines being added to indicate processing program version and date/time). There was some concern about snowballing the file size, so the information carryover idea will be considered a guideline, not a requirement.

  3. Persistence Blanking in Images -- A tangential point that arose from the discussion of the SIS's was that the requirements may be interpreted to include blanking out persistence objects in the coadded images, and no place in 2MAPPS has been identified where this is done. Some disagreement ensued over whether such blanking was preferable to providing a list of persistence source locations in the image and leaving the image alone, as well as whether ghosts and other probably identifiable artifacts were to be treated in this way. The possibility of leaving the image alone and supplying an overlay mask image was discussed; some objection to the proliferation of images was expressed.

    Whether to blank pixels or supply location information was deferred, but the place in 2MAPPS for doing either of these tasks was identified: GALWORKS, which has all the information needed in memory at one time.