By then about half the survey had been completed .
There he enlisted the assistance of Harold G Corwin of the University of Edinburgh , who continued to work on the catalog until 1981 , at which time he joined the Department of Astronomy at the University of Texas .
About half the survey had been completed .
There he enlisted the assistance of Harold G Corwin of the University of Edinburgh , who continued to work on the catalog until 1981 , at which time he joined the Department of Astronomy at the University of Texas .