You can download Astrometry 2.1 for Mac from our application library for free. The file size of the latest setup package available is 6.6 MB. The application lies within Education Tools, more precisely Science. Our antivirus scan shows that this Mac download is malware free.
From the developer:
Astrometry for OS X is a native port of the astrometry.net system, a web service server, and a GUI wrapper. It is tightly coupled with AstroImager and its image-solving feature, but you can use it as a standalone application as well. The astrometry engine is based on astrometry.net 0.65 and cfitsio 3.39. It doesn't use any python scripts or 3rd party image conversion programs, so it accepts only FITS files and doesn't produce any plots.
You may want to check out more Mac applications, such as AstroDSLR or Observatory, which might be similar to Astrometry.