A photometricity and extinction monitor at the Apache Point Observatory

David W. Hogg, Douglas P. Finkbeiner, David J. Schlegel, James E. Gunn

    Research output: Contribution to journalArticlepeer-review


    An unsupervised software "robot" that automatically and robustly reduces and analyzes CCD observations of photometric standard stars is described. The robot measures extinction coefficients and other photometric parameters in real time and, more carefully, on the next day. It also reduces and analyzes data from an all-sky 10 μm camera to detect clouds; photometric data taken during cloudy periods are automatically rejected. The robot reports its findings to observers and data analysts via the World Wide Web. It can be used to assess photometricity and to build data on site conditions. The robot's automated and uniform site monitoring represents a minimum standard for any observing site with queue scheduling, a public data archive, or likely participation in any future National Virtual Observatory.

    Original languageEnglish (US)
    Pages (from-to)2129-2138
    Number of pages10
    JournalAstronomical Journal
    Issue number4
    StatePublished - Oct 2001


    • Astrometry
    • Methods: data analysis
    • Methods: observational
    • Surveys
    • Techniques: image processing
    • Techniques: photometric

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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