Ok after fixing all the damage Yosemite did to my programs I have got it working in both nova and local modes in OS X 10.10. I added the following code after line 311: else: # OSX local # exe = '/usr/local/Cellar/astrometry.net/0.44/bin/solve-field ' if not self.havescale: # first rough estimate of scale options = opt1 + "--crpix-center -b /usr/local/Cellar/astrometry.net/0.44/etc/astrometry4100.cfg " cmd = exe + options + filename print '___________________________________________________________' print cmd os.system(cmd) self.update_scale(hint) print ("estimated scale: %.3f" % self.scale) print '___________________________________________________________' else: # fine tune with finer indices print "known scale ", self.scale, " used: ", self.help_scale.get() options = opt1 + "-b /usr/local/Cellar/astrometry.net/0.44/etc/astrometry4200.cfg " if self.help_scale.get() == 1: up_lim = self.scale*1.1 lo_lim = self.scale*0.9 options = options + "-u app -L "+("%.2f" % lo_lim)+" -H "+ ("%.2f" % up_lim) + " " cmd = exe + options + filename print cmd os.system(cmd) self.update_scale(hint)Local solves of the test files take about 6 seconds, this is similar to what I get solving my images so I am happy with that When I get some clear skies I will try this out for real.