https://arxiv.org/abs/1212.6182
[1212.6182] The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
Abstract page for arXiv paper 1212.6182: The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
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https://aa.usno.navy.mil/
US Naval Observatory Astronomical Applications Department
US Naval Observatory Astronomical Applications Department
us naval observatoryastronomicalapplicationsdepartment