James: "I think it's fair to say, though, that there is some problem with the simultaneous assumption that CSO coords are geo and that we are applying the ab/nut correction correctly." Yep. The relevant files are in /scratch/adam_work/plots/: models_noabnut_radec_0707.ps models_noabnut_rawcsoptg_radec_0707.ps models_oppositeabnut_radec_0707.ps models_oppositeabnut_rawcso_radec_0707.ps I'm afraid they're pretty confusing. 'noabnut' means no aberration/nutation correction was applied during the mapping process. 'oppositeabnut' means that an aberration/nutation correction that, according to the eq2hor and hor2eq texts, should actually convert heliocentric to geocentric, is being used on data that we believe is starting in a geocentric frame. There are two possibilities: 1. We are wrong 2. eq2hor/hor2eq are wrong. The 'rawcso' files have FAZO/FZAO "subtracted out" (removed) in pages 1 and 3, and FAZO/FZAO added back in on pages 2 and 4. 'rawcso' means that we're looking at the ra/dec the CSO gave without the users' FAZO/FZAO corrections. The non-rawcso have the NCDF ra/dec vectors, with precession correction applied (and some form of ab/nut correction), but the FAZO/FZAO are still present. THESE should be equivalent to Meredith's plots, e.g. where FAZO_SET/FZAO_SET are on the y axis. However, that's only true for pages 1 and 3. Pages 2 and 4 have FAZO/FZAO essentially double-subtracted, so they should be ignored. Pages 1 and 3 of the non-rawcso files should be equivalent to pages 2 and 4 of the rawcso files with the exception that the sigma-rejection used to choose the yellow points is different. So what's in each page? On pages 1 and 2, the red lines are my best fit to the yellow data, which is the black data with an iterative sigma rejection applied (i.e. reject at 1 sigma, recalculate sigma from good data, reject at 2 sigma). The blue lines are Meredith's models. The right side includes only the yellow data points with the red line subtracted. On pages 3 and 4, the same is pretty much true except that ONLY the altitude-dependent line has been subtracted: there is no fit to azimuth. Also, the 'sourcecompare' files are similar. I'd check those out too. I still don't have the extremely low RMS that Meredith saw. I'm going to go through and try to reject bad data points by hand to see if I can get to that level. We'll see.