Sliding Box for Uniform Photometry (SBUP)

The DPOSS plates are calibrated using CCD data taken at the P60. At times individual plates do not have enough CCD fields. We need to use those from adjacent plates in such a case. MEANSPLINES from SCO_CODE allows to transform to any plate the magnitudes of it adjacent plates to form a uniform system over a much wider area. The procedure involves overlap regions, star-galaxy classification and all that and is described on Steve's pages.

The procedure was initially carried out on non-overlapping 9-regions around the NGP and the SGP. This involved 36 central plates and their surrounding regions. For uniformity we are now using a sliding box methodolgy so that each plate, in turn, becomes the central plate to have its magnitudes defined by 9 plate wide CCD observations.

[~aam/dposs_bin/]sliding_box.pl is the program to use for this. It takes either one or two aruments. If used with a single argument, the argument is the plate number to be treated as the central plate. Thus,
sliding_box.pl 444
will run assuming that plate 444 is the central plate. If given two arguments, e.g.
sliding_box.pl 441 450
It will work for plates 441 through 450.

At present this is what the program does:
determine the 9-plate (or 8- or 10-) plate region surrounding the central plate, figure out who is whose immediate neighbour (using splines.list) and figure out 2- and 4-paths to these immediate neighbours. To the remaining plates it figures out the 3- and 5-paths. It then makes appropriate input files for MEANSPLINES in a directory having the same name as the plate number and copies the appropriate spline files there (from dposs:/aam/splines). It then CDs there and runs MEANSPLINES for each in.PLATE1_PLATE2 file. Once the meansplines are generated along with the appropriate plots, the auxiliarry files are deleted.

Wishlist: make more auxiliarry steps so that further procedures in the pipeline get automated.


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Last Outdated: 12 Feb 2001