Antique lens? Gun sight?

[rastinirv]

Obviously this is not something I dug up, except out of a box, but I'd appreciate your help. It's about 3 x 2.25 x 2.5 inches, heavy, brass, with glass optics. No writing on it anywhere except for the numbers. The cylinder turns about 120 degrees. It seems very well made. I just wish I knew what its application was. Old camera lens? Military gun sight? No idea. Thanks in advance for your help.

 

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[Retired Sarge]

Maybe from a sextant, similar set ups are seen on them. Let me see if I can find an example. If it is, being brass I'd say for nautical use versus aviation use.

In this old photobucket shot of my Bausch & Lomb A-8A sextant you can see the eye cup and on the lense.

 

[DizzyDigger]

With the attachment plate, it appears that it's made to
be mounted to a device. Microscopes and telescopes would
have removable eyepieces, although the calibration marks
could relate to a multi-power eyepiece.

Interesting...

 

[Charlie P. (NY)]

I think Ffuries is on target with a theodolite eyepiece. The +/- scale is a diopter adjustment (handy for those like me who normally wear glasses to use whatever instrument without them).

 

[dozer dan]

So what happens when you turn the dial? Any changes inside the lense? Is there possibly an iris?

 

[Back-of-the-boat]

A proctologist uses that. You sit on it for a better view LOL just kidding.

 

[rastinirv]

I have it at another location right now, but yes I do believe something happens when you turn it. Iris might be the word, but I'm not sure.