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Q: Identity of an unknown device ( No Answer,   5 Comments )
Subject: Identity of an unknown device
Category: Science > Instruments and Methods
Asked by: steview-ga
List Price: $25.00
Posted: 28 Sep 2005 11:14 PDT
Expires: 28 Oct 2005 11:14 PDT
Question ID: 573827
Identify use & manufacture of a tool. Possibly German in origin. 2
Aluminum rods each 48" long and 1.5" in diameter, which couple
together to form a long rod. Each rod has a black oval-shaped
"optical" device in the outer end, with the number 175418. The center
of the black oval shape is translucent plastic with with a bullseye.
There is a 1/4" molded channel on the side of each tube that runs the
length of the tube. The tubes feel as though they contain something,
as they are relatively heavy. No electrical connections of any sort.
There is a canvas and leather carrying case that looks custom-made for
the device. The first reaction of most people is that it is a
surveying instrument of some sort.

Request for Question Clarification by scriptor-ga on 28 Sep 2005 12:27 PDT
Dear steview,

I have an idea what the device might be; but I am not completely sure
yet. Have a look at these images:

Please ignore the fact that the depicted device is very old, from
1830. Yours must be considerably younger; the use of aluminium and
plastic clearly identifies it as a 20th century product. Ignore the
details, just look at the general layout - the rod with optical
devices at its ends - and let me know if it resembles the way the main
elements of your device are arranged.


Clarification of Question by steview-ga on 20 Oct 2005 07:46 PDT
Scriptor, you may be on the right track, but the "thing" I have looks
as though it's designed to be looked at  "sideways" at a 90 degree
angle, rather than looked "through" (along it's length) such as the
items you showed.
Wish I could post a photo somehow.

Sorry to be so long in clarification. I had browser problems that
Google techs had to help with.

Clarification of Question by steview-ga on 20 Oct 2005 08:03 PDT
The rangefider at doesn't look like it, BUT in the
accessories for the rangefinder the carrying case is very similar to
the case this is in, and the item at the top of the photo somewhat
resembles my item, except my item appears newer and is longer when
snapped together, and the devices on the end have a "bullseye" in

Clarification of Question by steview-ga on 20 Oct 2005 14:54 PDT
Myoarin-ga photo is the closest thing I've seen yet. Looks older than
mine, and mine snaps together in the middle rather than hinging, plus
mine has bullseyes rather than triangles, but I tend to think that it
might have a similar function.
There is no answer at this time.

Subject: Re: Identity of an unknown device
From: myoarin-ga on 28 Sep 2005 20:01 PDT
Perhaps a rangefinder, a "military or naval rangefinder".  The images
from the ends of the instrument were reflected through the tubes where
the viewer brought them to coincide and the could read on a scale the
distance to the object.
Your item with on 1.5 inch tubes seems rather lightweight, and you
didn't describe its functions, but maybe the critical central part of
the optics is missing.
Here is the whole "hit" for a site that mentions such, found with the search:
"naval rangefinder", which unfortunately does not offer much.  

[DOC] Archives of an email list on the history of binoculars. http ...
Dateiformat: Microsoft Word 6 - HTML-Version
I found a photo of a 4 meter Zeiss naval rangefinder with two 25X100, (cast body
model), aiming binoculars attached to it. I'm not sure if anyone else has ...
Subject: Re: Identity of an unknown device
From: physicsteach-ga on 15 Oct 2005 19:52 PDT
Here is another site that describes a Swiss-made optical
artillery rangefinder.  There's a photo showing accessories 
that look similar to the parts you mention:
Subject: Re: Identity of an unknown device
From: cynthia-ga on 20 Oct 2005 08:08 PDT
Possibly very old and outdated survey equipment, however I didn't see it here:
Subject: Re: Identity of an unknown device
From: myoarin-ga on 20 Oct 2005 13:30 PDT
Is your item someting like this:
Subject: Re: Identity of an unknown device
From: myoarin-ga on 21 Oct 2005 18:05 PDT
I hope it is, but yours seems longer than the one I found, if it is a
subtense bar.  But that could be due to use for english measurements. 
Here is a description of how a "subtense bar" is/was used:

Somewhere on this site the expression appears, but I couldn't find it,
but the text is very interesting if you have a little interest in
surveying.  The other pages of the site are too.  It talks about
sighting on wedge-shaped targets vs. bullseyes, which sounds like a
difference between yours and "mine".
Here is a site with two examples and photos of Wild subtense bars,
scroll down to the end:

Since yours snaps together and has a different length, I could imagine
that it is a British or American product.

"subtense bar" sounds like a good name for a place for surveyors to
unwind, reduce the tension after all that fine sighting and angle
reading.  :)

CHeers, Myoarin

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