Skip to content


Repository files navigation

Travis: Build Status CircleCI: Build Status Tag Version License

Automatic recognition of astronomical images; or standards-compliant astrometric metadata from data.


If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then is for you. Input an image and we'll give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.

We have built this astrometric calibration service to create correct, standards-compliant astrometric meta-data for every useful astronomical image ever taken, past and future, in any state of archival disarray. We hope this will help organize, annotate and make searchable all the world's astronomical information.

Copyright 2006-2015 Michael Blanton, David W. Hogg, Dustin Lang, Keir Mierle and Sam Roweis (the Team).

Contributions from Sjoert van Velzen, Themos Tsikas, Andrew Hood, Thomas Stibor, Denis Vida, Ole Streicher, David Warde-Farley, Jon Barron, Christopher Stumm, Michal Kočer (Klet Observatory), Vladimir Kouprianov and others.

Parts of the code written by the Team are licensed under a 3-clause BSD-style license. See the file LICENSE for the full license text. However, since this code uses libraries licensed under the GNU GPL, the whole work must be distributed under the GPL version 3 or later.

Code development happens at

The web service is at

The documentation is at

There is a (google group) forum at

Additional stuff at

Code snapshots and releases are at

For academic use, please cite the paper:

Lang, D., Hogg, D.W., Mierle, K., Blanton, M., & Roweis, S., 2010, Blind astrometric calibration of arbitrary astronomical images, The Astronomical Journal 139, 1782--1800.

Bibtex | Bibtex@ADS | arXiv | AJ | doi:10.1088/0004-6256/139/5/1782