PosMan Version 3 Status

The task of obtaining overlap position differences from the full working database has been broken down into two parts. A list of nights not included in the 2nd Release was made up and split between SHARIF (south) and NEBULA (north). Although extraction speed has been improved since the 2nd Release, the fact that we're now using the full working database is offsetting. During 26 days of processing 229 nights have been completed, yielding a rate of 8.8 observing nights per day of processing on the combined machines. If it continues at this rate it will take about two more months to process the remaining non-2nd Release nights. It should be noted that database performance is poor right now because of massive loading going on, implying that the rate may improve. On the other hand, variations in source density per observing night could drive the rate down. Add to this the fact that some scans from the 2nd Release nights will need to be run to pick up working database scans not in the catalog release database. All told, 2 1/2 months is probably a reasonable estimate of the remaining time needed to extract the differences from the working database. This should not present a problem since other tasks can be done in parallel.

II. Checking for Time Variations in Distortion:

Using a technique previously described, band-frame level distortion has been checked at 6 month intervals for both the Northern and Southern telescopes. Each check point required restoring the necessary pipeline files from several nights of processing and running GenDXY on the Cal scans from each night to generate the needed dxys files of bias-removed USNOA differences. The dxys files for each set of nights were then combined and the distortion was fitted using FitDXY.

Analysis of the distortion fits shows little change with time for either telescope.