What is function of this Zeiss Ktm/C4?

[cannonmn]

I've posted a slideshow and description here:

http://gs19.inmotionhosting.com/~mil....cgi/read/8542

Everyone wants to tell me it is rangefinder but I'm quite familiar with many styles of German Enfernungsmesser, and this is not one of them.

This instrument shows two overlaid images, and allows the user to find the small angle between two prominent objects. The images come not from the same general direction as with a rangefinder, but from opposite directions, the respective light paths entering either side of the device.

[mlespaul]

Believe it or not, I've seen this before. I need to check my picture archives to see if I made a notation or description of it. I think it's a training device for observation of the horizon and surface orientation. Some of the secondary gun armaments of the medium class ships had anti aircraft guns that could be dual-purpose for surface engagment. In order to make the switch the gunner had to re-orient the gun from open air field of view to horizontal surface view in order to assist the eye in tracking lateral movement of the target on the surface of the water, and they had a separate gunsight optic to help them do this.

This isnt that optic, but probably some training device that helped do that. Perhaps the kriegsmarine midshipmen were issued this on their "junior cruise", but I don't want to create a myth, LOL .

I'll follow up later after I pull the folder on this one.

[cannonmn]

Thanks. The key probably has to do with the fact that the operator matches two images using the star knob, then apparently goes to the smaller eyepiece and reads off the the small angle, formed somehow in the previous view, from the scale and crosshair.

[cannonmn]

One minor point of interest which someone could enlighten me on, is the Roman Numeral "IV" to the right of the eagle. In fact I think it reads "IV/I"

What does that Roman numeral, in that position, indicate please?

Is that related to the "/C4" in the Zeiss designation for this item?

[Stew]

Hi cannonmn, a very good question and I do not have an answer. I can outline where and when this Kriegsmarine property mark appeared on binoculars. A quick look thru the standard binocular texts : according to Hans Seeger's schedule of CZ/blc serial numbers it appeared on many Carl Zeiss Jena/ blc marked Kriegsmarine binoculars from 1939 to 1941. (but not all Kriegsmarine variants in these 7x50 and 8x 60 sizes ). Another variant appears in Steven Rohan's book on page 128 - this has a picture of a Kriegsmarine 8x60 binoc made by CZ Nedinsco - here there is pictured an Eagle over swastika and beneath is "M IV/a "
I note that Leitz/ beh Kriegsmarine binocular variants do not appear to use this M IV/1 at all. During this period they used an eagle over swastika and an M .
It would be good to learn what the M IV/1 actually signifies!!!

[cannonmn]

Stew, thanks a lot for that info. It is surprising how much about these things remains mysterious after all this time and all the collectors who have looked into the subject.

[cannonmn]

Does anyone have suggestions as to how to identify the function of this device? I emailed the Jena Optical Museum and got no reply, even though I phrased the question in German. They may either lack the staff to answer questions or they are completely focused on the older products, and have no records nor interest in the military line. Has enyone gotten a response form an inquiry to the Jena Optical Museum?

Since Jena was in what became the Soviet Sector of Germany, I'm guessing all military documents, especially engineering data, captured at Jena in 1945 went off to the Soviet Union.

[mlespaul]

Does anyone have suggestions as to how to identify the function of this device? I emailed the Jena Optical Museum and got no reply, even though I phrased the question in German. They may either lack the staff to answer questions or they are completely focused on the older products, and have no records nor interest in the military line. Has enyone gotten a response form an inquiry to the Jena Optical Museum?

Since Jena was in what became the Soviet Sector of Germany, I'm guessing all military documents, especially engineering data, captured at Jena in 1945 went off to the Soviet Union.

A better place to go is to the Zeiss Archive website. You can request documents, manuals they have on hand. They also have a database of items made before 1945 that they are working on. It's not bad but it still misses some items. Try there but be prepared to pay some $ for a copy of something they have.
http://www.zeiss.de/C1256B0500353C49/?Open

I did pull my folder on this one and yes, it's the same item with a different model number, but unfortunately, all I have for annotation is "handheld rangefinder" which might not be accurate, sorry. Good luck, let us know how it goes.

[cannonmn]

One input I got from Germany suggested that this may be a "Kantenmesser." They did not explain what such a device does. That name does appear to be a good fit to the "Ktm" designation printed on the device.

Does anyone know what a Kantenmesser does? I would roughly translate it as "tilt measurer" but tilt of what?

[Le Breton]

Ktm

Gents,

I believe this to be a Koincidenztelemeter, "Ktm" is the usual abbreviation. It can be found on some 3 and 4 meter basis Em's, but these measure distances, no angles. It superimposes two pictures, thereby allowing to measure an angle to the horizontal. The purpose of the instrument: I don't have a clue. Might have the same function as a Torpedoauswanderungsmesser but ment for use on smaller ships?

[cannonmn]

Kriegsmarine instrument Ktm. C4- what's it do?

https://m.youtube.com/watch?time_con...&v=b5KUTfCU0v8

Add photos

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https://springfieldarsenal.files.wor.../image135.jpeg

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https://springfieldarsenal.files.wor.../image137.jpeg

[Mikedenmark]

The roman IV next to the eagle refers to the office responsible for accepting equipment of a certain kind. Roman IV has to do with optics.
You will find different roman numbers on other types of equipment.

One for leather goods, another for shells, for cannons, and yet another for handguns, like the roman III/3 ? on a Mauser HsC pistol below.
http://luger.gunboards.com/uploaded/...Navy%20005.jpg
Roman III is responsible for guns.
Flaregun, III/3 navy accepted:
http://leuchtpistole.free.fr/Sommair...oleMod_1_4.jpg
Another III/2 here on a fuse:
http://www.warrelics.eu/forum/attach...2-img_0831.jpg

Here is roman II/2, ( or 3 or 8, 8 may be more likely), on saddlebags:
http://abload.de/img/37wf10.jpg
Another II/4, this time on a shell fuse:
http://www.warrelics.eu/forum/attach...2-img_0829.jpg

and roman V/1, which is on leather assessories for a bino:
http://www.warrelics.eu/forum/attach...lens-cover.jpg

The digit after the slash is a suboffice under the major department.
You will find different digits after roman IV for cannon sights and binoculars, as they are accepted by seperate offices under the main "umbrella" optics.
I have seen the break down of the navy acceptance offices once, many years ago, in a completely dull little german book. But to recall the title has, so far, prooved to be impossible. If I ever find it, I will post a copy here. The info is out there, somewhere.

A suggestion:
The KtM may indeed be a Kantenmesser. If translated into "corner", rather than edge, it may be used to check the angles from a cannon to the superstructure around it. There is a minimum free angle required for a cannon to be able to fire freely, without getting the trajectory influenced by blast reflections from the things around it.
So, you stand somewhere prescribed, on the cannon, then traverse it, (or elevate it) using this KtM to check it has a free space to fire. That it doesn´t shoot up corners or that grenades get´s too close.

This will be done on installation, and again, if you store goods on deck somewhere around the cannon.
A device with a similar function is known with the field artillery, the deckungswinkelmesser, where the cannons must be able to fire without getting too close to the top of the holes they may be standing in. Only that is up and down, not sideways.

But it is just a suggestion.

[cannonmn]

Thanks Mike, will certainly check that out.

Meanwhile I made up this description of operation and speculation about possible navigation use.

My latest thoughts:

Operation: User first sets the density filter wheel to the appropriate setting of the four filter glasses provided. The darkest filter allows direct observation of the sun with no discomfort. The variable-density filters only filter light entering the optical port facing directly to the user's right. The user adjusts each eyepiece separately for focus.

User looks into the larger eyepiece to see a split image formed by two small telescopes of about 4-power magnification mirrored at objective end so their axes point directly to user's right and left respectively, through small round glass windows in either side of the device. The two small telescopes are articulated so their axes may be diverged within the range of -2 to +2 degrees to obtain image coincidence, and the exact angle read-off as described below.

When the images from right and left telescopes are brought into coincidence by the user adjusting the divergence by turning the small black knob, the divergence angle may be read by the user through the smaller eyepiece. The divergence angle scale is graduated in minutes and is read where the black cursor line crosses the -2 to +2 degree scale. The scale and cursor are illuminated by light entering a small, round, frosted glass window in the front of the device, opposite the two eyepieces. The device has no provision for night-time illumination of the scale and cursor, which may mean it is only possible to use it during daytime. That fact may help narrow down the list of possible uses for this device.

Conversely, if the user has a pre-calculated angle of divergence, he may set the angle on the scale, then looking through the large eyepiece, mark the time at which the two target objects' images coincide.

The most striking feature of the operation of this device, as opposed to most other military optics, is that it was designed only for optical targets on opposite sides of the user. Since it was probably designed for use aboard a warship or submarine, the use may involve at least one horizon and perhaps a celestial body at the time of day that it is within two degrees of the horizon. If this was the intended use, note that, for example, the device would could determine the angle between the rising sun to the east and the western horizon. Since eastern and western horizons viewed from a ship in open ocean would be at the same distance, in sextant-user terminology, the sun could be "brought down" to the horizon opposite to the one from which it was rising. The instrument would measure the same angle above the horizon when comparing eastern sun vs. western horizon, as it would if it could compare eastern sun vs. eastern horizon, given that the two observations were made at the same time and date. The device may have been invented to solve a chronic difficulty of observing the exact time of sunrise or sunset with a hazy horizon adjacent to the sun. The sun is only used here as an example; another celestial body's rising and setting may also figure into this. The device may have been developed for use by surfaced submarines where the observer is very close to the water and hazy horizons may have been more of a problem than aboard surface ships.

springfld.arsenal, 46 minutes ago EditReportBest Answer#21+ QuoteReply

[Mikedenmark]

The filters make my suggestion earlier very unlikely.
If there is a yellow filter, that is usually used in mists or fog. The dark filter suggest observation against either the sun or a searchlight. +/- 2 degree is very little, and in a hand held instrument ??????
I think mlespaul may be the right one to solve this.

[cannonmn]

Thanks again-no yellow nor Amber filter, the filters include the very dark one, like in an arc welder's mask, a clear one, a slightly-smoky one, and a very smoky one (4 positions only.)