I realize the answer to this question is probably: "it varies"
If you were to say on a typical night, how many objects/hour are you observing? Does it depend on an evening's observing program?
Saaaayyyy... Suppose one wants to OFFICIALLY observe (look at, see, log) More celestial objects (cept single stars) in one night, than anyone else in history? I think that might be pretty easy to pull off:
You get an agile, precise, big, ergonomic GoTo scope under great dark skies and pre-program it to dead-center pre-selected Giant List of objects. The Computer (and and/or assistant) announces each object as the scope slews and locks on coordinates. e.g. assistant, "M13 Great Globular." Observer, "Thar she blows! Giant ball o' stars dead center... NEXT!" ... Hour after hour, nebulae, clusters, galaxies, double stars... each and every one dead center. The list criterion is that the objects are not too crazy tough for this scope... things that an experienced, able-bodied observer can see fairly easily with this big, precise scope under these excellent conditions. Every object is locked dead-center and you blurt out a few words describing it. About one in ten is an intentional negative (dead sky) location, trying to get you to claim you see what is not there. e.g. "NGCabcd small galaxy." The appropriate response is, "Umm Uh Ummm... No Sighting... Next!" So, it goes on like that, hour after hour...
The scope could even have a motorized parfocal eyepiece turret, filters, etc. auto-optimized for each target. You could smoke cigars thru the same tube that water and Hershey's Syrup come thru... Got it all figured!
I’ll bet one could log 100 viewed objects an hour for 15 hours, with 99% accuracy (the other 1% comprising true negatives and false positives).
Some experienced witnesses would be monitoring the session and, of course, the Guinness Representative would be there, Officially recording the event.