2012-06-10

Gaia subtleties

En route back to New York, I read this paper by Bastian & Biermann (recommended by Anthony Brown) about the astrometric calibration issues that arise in the Gaia satellite because of the finite drift-scan integration time across the CCDs. There are several valuable insights in the paper, but the most amusing to me is that very rapidly variable objects will obtain signals in Gaia with a different effective mean time on the CCD and therefore be subject to a very slightly different spacecraft attitude model, in some sense. I don't think this will be problematic for many stars, but at Gaia precision, a lot of things matter. It is one of the many reasons I love interacting with the Gaia community.

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