ID function of this Kriegsmarine optic?

Every five years or so I reach out on various forums, attempting to pin down the function of this WWII German Navy optical instrument. It has two eyepieces on one end, one optical port on the side and one on the end opposite the eyepieces. Here's a forum discussion with more detail. It measures about 7.5 in. X 3 in. X 1.5 in. So far no one in the world is sure of what it does.

Forum:

http://wehrmacht-awards.com/FORUMS/showthread.php?p=4915266

Photos:
https://springfieldarsenal.files.wordpress.com/2016/01/image133.jpeg

https://springfieldarsenal.files.wordpress.com/2016/01/image134.jpeg

https://springfieldarsenal.files.wordpress.com/2016/01/image135.jpeg

https://springfieldarsenal.files.wordpress.com/2016/01/image136.jpeg

https://springfieldarsenal.files.wordpress.com/2016/01/image137.jpeg

 

Assume you've asked here>
http://szextant.blogspot.com/2014/11/143-kriegsmarine-telescope-80-mm.html

 

So, it measures the angle between two objects?
Just some some thoughts....in celestial navigation, that would be a type of sextant, used for determining longitude at sea; used vertically.
A Wikipedia article https://en.wikipedia.org/wiki/Reflecting_instrument
indicates that optical instruments for measuring angles are used horizontally at sea for hydrographic surveys; and on land, as a surveyor's sextant.

This has no attachment point for a tripod, and none of the black plugs unscrew to expose a mounting point?
And it would seem to have some military use.....I'm stumped.

 

The more I look at this the more I suspect it's a compact, waterproof sextant . Possibly for subs.

 

Thanks, I looked over that binocular site, interesting stuff but I don't think my object would fit into their scheme. I've used various sextants back when I was a navigator and I'll see if this little thing could provide the precise angle data needed, somehow I don't think so but I'll look again. There's no mounting hardware on it.

 

There wouldn't be anywhere to mount it on a sub due to time issues of emergency submersion and it would have to be small to move it about and store it...
Could quickly take the reading, set/lock it and go below to figure it out.

 

I'm re-acquainting myself with the workings. The smaller eyepiece is used to read an internal linear scale that goes from -2 to +2, which must be degrees since each unit is divided into 60 parts which must be minutes of angle. Well that is enough accuracy for a celestial fix if "within a mile" is close enough. But that total range of 4 degrees is only relative to something else we don't know yet and you need absolute elevations of a celestial body to navigate. Maybe it is for solar observation only? There are a number of progressively dimmer light filters selected by the large black knurled ring. The small black knob seems to be an angle adjustment and moves a prism or mirror inside, so when you see certain things aligned inside, you stop turning the knob and read off the number. Maybe.

There are really three optical ports but I think the front one opposite the eyepieces is there only to admit light to illuminate the number scale I mentioned. The important ports are on opposite sides of the device. So somehow this must be used to compare objects, horizons, or some things that are on opposite sides of the device. One side view needs "sun filters" and the other doesn't. ??? Well I'm kinda thinking out loud here-I think this will be the year we figure out what this thing was built to do. Tomorrow when sun's out I'll take it outside so I can get images out both opposite ports and see if any nautical applications pop into my head.

 

Filters for sun makes sense and not filtered for moon/stars...so maybe....
~
This may be the only one ever made you know..... Tester.

 

I did see another one sell at an auction for $1100. Maybe ca 2008. Mine is serial no. 37 so there musta' been at least 36 others.

 

WOW!!!!
Not necessarily...... The others could've been poor or failures.
I'm out>>>>>>>>>>>>>>
Nite!

 

More details on how it works: The optical port inside the filter-selecting wheel looks straight out the side of the device. The port on the opposite side looks straight out of that side. The large eyepiece views a split or superimposed image, what one port sees overlayed on what other one sees. The small black knob moves one image laterally over the other, I think the moveable image is from the port inside the filter wheel (let's call it port "f.") The other port we'll call "o." So you can set the darkest filter, point port f at the sun. and see a white ball no brighter than an incandescent lightbulb superimposed on view out of port o. When you look in the small eyepiece, the black cursor line lines up on the -2 to +2 degree scale to show what I think is the angle between the sun (or whatever) in f and, for example, the horizon you see in o.

 

YES!!!!! YAY!!!
Do we have a winner????
~
I was also wondering if it was to help view targets and ranges in varying conditions difficult to determine with the naked eye.
~
So now what?
Going to auction?

 

No auction, I like this thing and I think it is in the permanent collection-let the heirs figure out what to do with it. Anyway I'm still not 100 percent sure exactly how it was used and probably won't be until I find an original technical manual or official handbook for it.

After reading this nice compact summary of navigation instruments I think it is possible that the thing is a modern version of the ancient Arabic "kamal" but who knows, investigation goes on.

http://www.mat.uc.pt/~helios/Mestre/Novemb00/H61iflan.htm

 

Ah well......... I was hoping for a cut.

 

Spring, you have the most interesting finds that I haven't a clue about!!! I didn't read this thread until about an hour or so ago. I was hoping some day I might be able to recognize one of your prizes. My first impression on seeing the pics was possibly a rangefinder of sorts, but knew probably not. I did wander around a bit hoping to spot a similar, of course no luck. Just a few minutes ago wandered back over here to final look at that thread you linked to where some one suggested a "Koincidenztelemeter." I googled the word to see it or something like it "Koinzidenz entfernungsmesser" were coincidence rangefinders. I now see you figured it out. I have never come this close to a guess on anything you have posted.

--- Susan

 

BTW, meant to add to the above reply, while wandering around trying to spot something similar, I stumbled on websites dating Carl Zeiss serial numbers. The s/n 192,321 on this instrument on those websites dates to 1912!!! That was a big surprise until I realized the s/n listed were for Zeiss lenses.

Charts of Carl Zeiss are at the bottom of the page:
http://motamedi.info/serial.htm

"173,418-200,520 1912"

--- Susan

 

Thanks Susan, yes I guess those numbers must be for lenses as you said. The markings on the device I think put it in ca. 1938-45, and there are collectors who could pin it down precisely. One issue with Zeiss- Jena is that Jena was occupied by the Soviet U. in '45 and apparently all the Zeiss factory except the bricks was packed up and sent to Russia, including the documentation. The PhD who handles such records as are at the present Zeiss museum in Jena wasn't able to find anything on the KTM. C/4. But I'll keep looking. I got some rough, sloppy video through the eyepiece as I was experimenting with the device today, and if it looks like anything of interest I'll post a link to it later.

 

Hmmm. Someone in Russia might know where all the paper records are. Hope they're not in a damp/flooded basement, or dilapidated, leaky building.

Wouldn't that be something to discover all the Zeiss factory paperwork and plans after all these years. People from all over the world are finding this site by searching with key words that lead them here, so it could happen.

 

Thanks. Am now watching some of the many tube videos with WWII Kriegsmarine footage, maybe I'll see a ship's officer using one of these things, or with the distinctively-shaped carrying cases strapped around his neck. Lots of interesting footage there even if none of the instruments show up. Will post the video on a couple of specialized Kriegsmarine FB groups. Somebody's going to know.