Thank you, Binastro, for this impressive list.Binoculars are probably limited to 100x because of collimation problems.
Unless you include the enormous Alvan Clark? 6 inch binocular telescope, which probably had the same limits as the 6 inch telescope.
My friend made several 150mm binoculars using 150mm f/8 Chinese scopes and mirrors.
There is an 8 inch amateur British binocular, with folded optics.
The Ross fortress of Malta 6 inch plus binocular made with old Zeiss objectives.
An Italian binocular of about 10 inch aperture.
There were three Zeiss 30cm binoculars on rotating mounts that weighed over a ton.
I think they were destroyed.
There is the Japanese 180 binocular and a 250mm binocular in a Japanese museum.
I suppose the APM 30cm binocular is good at 200x.
Probably $500,000.
Mirror binoculars of 16 inch aperture.
But collimation can take an hour when moved to a star meeting.
Or the professional binocular telescope of several metres aperture.
I have a Japanese 25x-135x80 binocular that is well aligned up to 135x, but shows no gains above 80x.
Even at 80x it is no match for a fine 80mm telescope.
Personally, I have had no use or desire to own large binoculars.
One of the best planetary observers uses a 16.5 inch Dall Kirkham with a binoviewer.
Regards,
B.
Clearly a lot of very talented people worked hard to create these massive instruments, even though the mechanical aspects are serious handicaps.
I don't understand why the binoviewer option was not the preferred choice, it eliminates more than half the mechanical and optical costs, with no obvious deficiencies other than possibly the much discussed 3D effect, if that is even perceptible in an astronomical or air defense observation.