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As of April 13, 2015 the archive is now using the STScI Single Sign-On (SSO) identity manager. To check on your account click here. For more information about how accounts were transitioned click here.


We would like to acknowledge the CASB branch for providing the majority of online information available from MAST. We recommend that users consult the CASB website for the latest information on the Guide Star Catalogs.

Please e-mail questions regarding the Guide Star Catalogs to