Top of the pier visible as you come up the stairs. Insulation may have been used to do the floor from the warm room below.
RASC Hamilton Centre 1979_08
Scanned by Colin Haig 2006-03-23 to 2006-04-03
Scanned with Nikon Coolscan V ED.
These slides had a date on the slide mount, 1979 08, for the Marsh building construction at the Hamilton Centre Observatory.
Not sure when actually taken or when developed.