What would have been used to view a large stereoscope image?

I have been finding some very nice and rare larger stereoscopic images lately and when using my typical handheld stereoscope viewer I notice you can't see the entire image. I have to hold it freely and move it up and down to see it all. What would have been used to view the image in it's entirety? Anyone know?

 

Maybe something like this that can be moved out for bigger pictures?

 

I have one like that but when I move it out that far it goes out of focus.... interesting! I was thinking possibly one of the old tabletop ones

 

My grandfather used to have one and when we went to visit him, he would let us use it - very carefully. Perhaps there is a model for bigger cards, maybe an earlier one.

 

It might be for a Brewster? here's a a Wiki article:
https://en.wikipedia.org/wiki/Stereoscope

 

You'd most likely need a Holmes type hand held or open table top unit (graphoscope) for the larger cabinet card sized views. The enclosed ones were older and meant for "standard" sized views only. The Holmes type viewers vary widely and some have much larger lenses than others, which would probably help in viewing the larger cards.

 

The larger size cards didn't appear until the 1870's.

https://www.vintagephoto.com/reference/dating.html

Larger, Cabinet sizes (5 X 7)
Square corner 1870 - 75
Rounded Corner 1873 - 90

Most of the ones i've seen were later 1870's into 1880's.