Astrometry.net is an online service that provides astrometric calibration metadata for astronomical imaging files that pack coordinates information. The service comes with index files that contain the information needed to solve images by comparing your photo with predefined sky marks.

Astrometry is a standalone application designed to be a port for the Astrometry.net online service. The app comes with a graphical user interface, a built-in web server, and can download the Astrometry.net index files in no time.

To get started, simply launch the Astrometry application and the utility will automatically start the embedded web server. The Astrometry user interface is represented by two different windows: one for managing the index files, and the other for solving FITS files.

Within the Astrometry Index Manager window, you must select the index files you want to download or remove. For your convenience, Astrometry keeps them organized in two columns, depending on the source catalog: 2MASS or Tycho-2.

Astrometry also provides quick access to the Astrometry.net documentation that includes extensive details about the index files, so you can determine which ones you need to use.

On the other hand, the Astrometry Solve window allows you to load FITS image files stored locally, and can easily solve them. You can see the progress log in the Astrometry Solver window, while the utility generates the metadata loaded files in the same location as the source FITS image.

To conclude, Astrometry provides a standalone solution for using the Astronomy.net service and engine in a user-friendly and streamlined manner. The app can download index files from different catalogs and can readily solve FITS files with very little user interaction.