(covers information from several alternate timelines)
The astrometric database was a database of star charts and astronomical phenomena aboard the USS Voyager. In contained all information from the Borg Collective and the information was accessed from Astrometrics.
In 2374 of an alternate timeline, when Voyager was heavily damaged by several Krenim warships, Captain Kathryn Janeway asked Seven of Nine if the astrometric database was still intact to gather information about the changes in Grid 005 due to the temporal incursions of Annorax and his weapon ship. (VOY: "Year of Hell")