Mount Wilson Catalog of Photographic Magnitudes in Selected Areas

astronomical work

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July 1, 2026

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The Mount Wilson Catalog of Photographic Magnitudes in Selected Areas was a significant astronomical catalog published in 1930. It was a leading reference for celestial photometry for many years. This catalog was part of a larger effort to map the sky, which includes not only positions and motions of stars but also their magnitudes and colors.1

Photometry is the measurement of the brightness of celestial objects, which provides information about their structure, temperature, distance, and age. The catalog focused on "selected areas," which were well-defined regions of the sky containing stars of various types used as comparison standards. This work was crucial for studies of galactic structure, requiring accurate magnitudes for both bright and faint stars.21

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Photometric catalogs
…standards of comparison, and the Mount Wilson Catalogue of Photographic Magnitudes in Selected Areas (1930), made about 20 years later, was for many years a leading reference for celestial photometry. Today several catalogs of photoelectric measurements in three or more colours set the standards for precision magnitudes.
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…standards of comparison, and the Mount Wilson Catalogue of Photographic Magnitudes in Selected Areas (1930), made about 20 years later, was for many years a leading reference for celestial photometry. Today several catalogs of photoelectric measurements in three or more colours set the standards for precision magnitudes.
Read More