Might be Brian Carr on the roof.
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. Abbreviations: JMH - written on the slide, likely the photographer, not sure who JMH is.