I think that they still do sneak a peak once in a while, usually to check on the rough focus of the telescope before inserting the photographic plate.
Time is valuable, and optical inspection is very inefficient.
Many astronomers do enjoy looking through their own telescopes just like any other 'amateur astronomer' and many of us have small telescopes at home, in a closet. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer .