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Tables format for imwcs
In order to use the imwcs command, like in this example:
imwcs -wvd img.cat -c ref.cat -h 100 -t 10 -q i image.fits
we need to insert the two tables img.cat, as the photometric catalog from the image (based on a rough detection), and ref.cat, as the catalog which we cross-correlate (reference catalog). But there is a specific format for these tables.
> Since the parameter “d” is used (DAOPHOT format) then the catalog img.cat is simply a 3 column text file with white-space-separated numbers on a line. The 3 columns are X and Y positions in the image (pixels) and MAG (a rough estimate of magnitudes). It is better to sort this catalog to the magnitudes. Example:
6629.311 43.663 -3.09156 69.331 2907.654 -2.75876 103.621 7751.257 -2.25899 2236.000 171.468 -2.02499 134.441 4506.971 -2.00035 ...
> The reference catalog should follow the Starbase tables, with some comment lines at the beginning and 3 columns again but tab separated. The 3 columns are RA and Dec (in degrees) and magnitudes. Example:
KEY1 1 KEY2 2 KEY3 3 RA DEC MAG -------------------------------------- 1.2879293234e+01 -7.3433459865e+01 0.0004802001 1.3764910094e+01 -7.3720846808e+01 0.0005518933 1.4358272653e+01 -7.3178757712e+01 0.0008463736 1.2396733738e+01 -7.3172484011e+01 0.0008719206 1.2431328059e+01 -7.3145855608e+01 0.001443057 ...
For more check the reference page for imwcs tool and its flags (which we do not discuss here now).
[A possible useful link is how to use sextractor to produce a table as an input to imwcs.]
