xy2sky_float_2_psfind.py

Process a list from xy2sky (see below) and create a list of X,Y,Ra_deg,DEC_deg for input to psfind.sh to derive a plate scale (in arcsec/pix) estimate. This same file can also be sent to the code "pafind.sh" to determine a direction for the NORTH vector.


To get the initial input list:
% xy2sky -d a.fits @data.xy > dat.RaDec

To run this code:
% xy2sky_float_2_psfind.py dat.RaDec > A.list  

Then you can get plate scale with:
% psfind.sh A.list

The "_float_" part of the routine name derives from the fact that all of the numbers in the input list are floating point format. Without the "-d" flag when xy2sky is run, the Ra,Dec would be in sexigecimal format and more transformation would have to be performed before psfind.sh could be run. Below is a sample of the type of ASCII file that this code generates:

S1
1039.500 1041.500 39.01563 65.74215
S2
1039.500 1873.100 39.06077 65.97400
S3
1054.013 1872.973 39.05080 65.97428
S4
1068.523 1872.593 39.04082 65.97450
S5
1083.023 1871.960 39.03084 65.97465
S6
1097.509 1871.074 39.02085 65.97472

Each point has a text name (e.g. "S6") and line of floating pont data that is:

column 01: X in pixels column 02: Y in pixels column 03: Ra in degrees column 04: Dec in degrees

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