This is a little wrapper script that runs RD2XY to compute sky offsets (in arcsecond units) for a pair of Ra,Dec positions.

 
ra_dec_offsets 05:05:30.60 +52:49:53.8 05:06:35.952 +52:49:53.95 
      -592.243          1.272        592.245      89.877

To get a usage message: 
% ra_dec_offsets 
Usage: ra_dec_offsets 10:45:10.90 +12:00:10.0  10:47:49.90 +12:34:57.0 
arg1 - RA0 of projection center in sexigecimal format.
arg2 - DEC0 of projection center in sexigecimal format.
arg3 - RA (sexigecimal) of offset position.
arg4 - DEC (sexigecimal) of offset position.

This shows the files created and how to see a useful 
explanation of what comes out of ra_dec_offsets:
% ls 

ra_dec_offsets 05:05:30.60 +52:49:53.8 05:06:35.952 +52:49:53.95 
      -592.243          1.272        592.245      89.877

% ls 
rd2xy_gnomSP.out_explain 

% cat rd2xy_gnomSP.out_explain 
Explanation of rd2xy_gnomSP output: 
Col01 = X in arcsec (-X to East)
Col02 = Y in arcsec (+Y to North)
Col03 = Radius in arcsec
Col04 = position angle (degrees CCW from North towards East)

Recall that I also have the code RA_DEC_SEP. It can do the same sort of calculation as above:

Recall, I have an interactive tool: RA_DEC_SEP
Position 1:  05:05:30.60 +52:49:53.8
Position 2:  05:06:35.95 +52:49:53.9
a(x,y) arcmin              =      -9.8702      0.0203
Separation in Degrees      =       0.164504
Separation in arc_MINUTES  =       9.870251
Separation in arc_SECONDS  =     592.215027

*** Cons for this:  
  1) it is interactive 
  2) it gives no  angle info 
  3) requires rigorous format of input ra,dec strings