View an image that has an initial WCS solution already installed (such as that derived with the wcs_getA script) or from rough_wcs_acam .
wcs_refine Usage: wcs_refine 20160617T051024.8_acm_sci.fits 17.0 3.0 0.5 11.5 red 4.0 arg1 - image name arg2 - V magnitude limit in USNO catalog arg3 - search Radius in arcmin arg4 - stellarity low (0.5) arg5 - stellarity hi (11.5) arg6 - color of markers (red) arg7 - radius of circle markers in pixels (5)The arguments above are pretty self-explanatory. The search radius is just the size (in arcminutes) around the center of the image that will be used to collect sources from in the USNO catalog (USNO-B1.0). Only sources brighter than Vlim (argument 2) are gathered. Finally, we may want to restrict our fit targets to be only within a certian range of stellarity. Arguments 4 and 5 let you do this (stell=0 not stellar, stell=11 very stellar). Yes, the stellarity scale "goes to 11".