First USNO Robotic Astrometric Telescope Catalog

URAT is a follow-up project to the successful UCAC project using the same astrograph but with a much larger focal plane array and a bandpass shifted further to the red. Longer integration times and more sensitive, backside CCDs allowed for a substantial increase in limiting magnitude, resulting in about 4-fold increase in the average number of stars per square degree as compared to UCAC. Additional observations with an objective grating largely extend the dynamic range to include observations of stars as bright as about 3rd magnitude. Multiple sky overlaps per year result in a significant improvement in positional precision as compared to UCAC.

Data and Resources

Additional Info

Field Value
Maintainer Tess Jaffe
Last Updated February 17, 2026, 00:45 (UTC)
Created April 1, 2025, 13:31 (UTC)
accessLevel public
bureauCode {026:00}
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harvest_source_id b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title Science Discovery Engine
identifier ivo://irsa.ipac/usno/catalog/urat1
landingPage https://irsa.ipac.caltech.edu/data/URAT1/urat1.html
modified 2026-02-16
programCode {026:000}
publisher NASA/IPAC Infrared Science Archive
resource-type Dataset
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theme {Astrophysics}