The new machine on which POS will run, lugosi, had arrived on the loading dock as of meeting time (at least 728 pounds worth). J. White reported that the current version of POS (known as bigpipe) has been running scan 057 of 940601 (a Ks scan of M92).
R. Cutri reported that the recent observing run on Mount Lemmon had several nights of sub-arcsec seeing, and good photometry and images of more than 70 galaxies were obtained. These were galaxies previously detected by the galaxy processor. Approximately half of the galaxies were observed with an image resolution of about 0.9 arcsec/pixel, with the remainder at about 0.3 arcsec/pixel. These observations will allow good truth tables to be generated for use in the development and testing of the galaxy processor.
R. Cutri also reported that source lists produced by the POS runs up to the point just prior to band merging will be made available in ASCII format for limited access via the web. New source lists will be added as each night's processing is completed. Analysis tasks will begin as soon as the data they need are available. By 1 August, the first pass through the new data should be complete. In addition, some TBD restricted access to raw data and images will be provided. This is in response to science team requests. The raw data will be copied to tape during initial processing and shipped to the recipients, who should be identified soon. Images will be available via ftp with password control.
B. Light reported that association of the new seeing parameter with corresponding KAMPhot PSFs will be extended to the new PSFs computed by J. Fowler by Moffat-broadening of the real 940601 PSF, and KAMPhot changes to use the seeing parameter to access the appropriate Moffat-broadened PSF have not yet been made but appear to be easy to implement.
=====================| Attachment Supplied by G. Kopan |===================== A measure of seeing has been incorporated into the prototype for the 2MAPPS STATS program (bumps). This measure (along with other diagnostic measures) is currently being written into a single-line file with a name of the form: BfSSS.pfrac where: B - band (j,h, or k) SSS - scan (i.e. 001) This file can be generated immediately after CFLAT is run, and copied to the sSSS/sdata directory, to be used by KAMPHOT and other downstream programs. The 'bumps' program runs in ~60 seconds on a typical scan on karloff. The file contains the flattened frame file root (e.g., kf001), the S/N threshold, and the 20, 40, 60, and 80 percentile values of the measure (described below). These files have been generated for simulated data(*) for a range of input 'seeing' values as summarized in the table below: scan >S/N 20% 40% 60% 80% (seeing) -------------------------------------------------------------------- kf001 20.00 0.5834 0.6480 0.6917 0.7358 (1.5") kf001 20.00 0.5273 0.5871 0.6300 0.6698 (2.0") kf001 20.00 0.5091 0.5682 0.6075 0.6471 (2.2") kf001 20.00 0.4906 0.5457 0.5872 0.6243 (2.4") kf001 20.00 0.4884 0.5396 0.5771 0.6140 (2.5") kf001 20.00 0.4777 0.5327 0.5678 0.6057 (2.6") kf001 20.00 0.4663 0.5165 0.5530 0.5898 (2.8") kf001 20.00 0.4511 0.4981 0.5337 0.5704 (3.0") The 80 percentile parameter is the best indicator of the seeing; the lower percentiles can be used as diagnostics, as they are more sensitive to 'false broadening' than the 80 percentile value. These parameters are estimators of the 'enpixelated energy' of a point source centered on a pixel. The parameters are percentiles of a histogram of a parameter computed as follows: - the parameter is that fraction of the total energy (above the median background) of a source which is contained in the peak pixel - only sources whose centroids are within 0.3 pixels of the center of the peak pixel and are over the S/N threshold are histogrammed This measure is a sensitive measure of the broadness of the optical psf for those point sources centered on a pixel. The 80 percentile is used as a robust measure due to the following confounding factors: - Confused objects (confused point sources, saturated point sources and associated diffraction spikes, galaxies and other extended structure) have lowered 'enpixelated energies' and pump up the lower part of the histogram - Lower S/N objects smear the histogram The current estimator is a prototype, and subject to errors of 2% or more due to confusion (M92, 3rd mag star), which can translate into a 5-10% error in 'seeing'. Galaxies are usually at a low enough density to have little effect on the 80th percentile. Techniques to reject confused measurements are under investigation and will be incorporated. This measure is relatively robust, has the advantage of simplicity and can be evaluated early in the pipeline. Suggestions for improvements or better techniques are welcomed. (*) - simulated data provided by Bob Light & Sherry Wheelock