Apply gnomonic (TAN-) projection to Ra,Dec values in an input CDFP file. The gnomonic projection is commonly used in many astronomical images (CRTYPE = "RA--TAN","DEC--TAN"). As shown below in Figure 1, this projection insures that any Great Circle will project to a STRAIGHT line in the transformed image.

cdfp_proj.sh usno_all.cdfp 12.39777 -10.37737 1.35 > cdfp_proj.cdfp 

arg1 = name of input cdfp00 file
arg2 = RAo deg  (floating point)
arg3 = DECo deg (floating point)
arg4 = scale in arcsec/pixel of image you are fitting

FIGURE 1: A demonstration of the gnomonic projection.