RedactedNarrative: While navigating by a star fix owner went off course and aground.  Owner states that he regularly navigates at night by sighting on a star.  Apparently he misidentified the star and went off course.   Boat went aground throwing OPERATOR 1 overboard.  Unhurt OPERATOR 1 swam to shore recovered a blanket from his boat and spent the night on the boat.  Shore line residence found the boat in the morning and notified Sheriff's office.  Marine 4 responded.