Astrometry.net
Published on 17 Jul 2007 at 1:26 am.
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Filed under Astronomy, Computation, Exploration, Internet, Photography, Research, Space.
The 2007 Data Mining in Aeronautics, Science and Exploration Systems (DMASES 2007) meeting was held recently in Mountain View California (June 26-27, 2007). Ashok Srivastava had asked me to chair the Science Session, and we were fortunate to invite a wide array of excellent speakers. Among them was Sam Roweis who is doing a sabbatical at Google, and presented a Live demonstration of “astrometry.net“. In an earlier post (which has been deleted) I described this endeavor as GoogleSky, however Sam emailed me to explain that he has nothing to do with GoogleSky, which was started before astrometry.net. Roweis works on Astrometry.net with colleagues: David Hogg, Dustin Lang and Keir Mierly as a collaboration between Google researchers at the University of Toronto and New York University. Google will get involved when they are ready to implement the system at a large scale.
Astrometry.net is poised to revolutionize astronomy by making any and all images of the night sky taken over time accessible to astronomers and those who perform data analysis or data mining on astronomical images. This includes images ranging from those taken by the Hubble Space Telescope (HST) to those taken by a tourist who happened to catch a portion of the night sky in their photograph.
Astrometry.net can take ANY image of the night sky and identify the image with respect to the precise astronomical coordinates. Astrometry.net is so good, Roweis explained, that theywill not need to rely on any information from the photographer; so good that they will not trust the information from the photographer. Roweis had intended for the audience to supply a set of astronomical images to be identified, but we did not have time to set that up beforehand. Instead, he downloaded the Astronomy Picture of the Day and uploaded it to the NYU server for identification.
Roweis explained that the problem is not as complex as one might think. Astrometry.net begins by selecting the stars in the image. These stars are then compared to a database of millions of stars, and matches are found. Surprisingly, only a handful of matches are needed to uniquely identify the image. When the results are examined, many stars in the image do not match to the limited database, and many stars in the database do not match to the image (due to clouds, exposure, etc.) The problem is merely that of matching points… not trivial, but overall straightforward.
In the future Astrometry.net intends to implement planet matching which may allow them to identify the time of the photograph in addition to the sky region.
Similar projects can be found at:
http://www.wikisky.org
which is the same as
http://www.sky-map.org/
Kevin Knuth
Albany NY
