Help identifying mystery Voigtländer lens from the 1860'ties

[loman]

Hello Everyone.

I have the front cell (or at least it sems like the front cell) from a voigtländer lens made in the 1860'ties.

If anyone knows what kind of lens this belongs to, or if it's a standalone lens, your help is much appreciated.

Here's what's written on it:

Voigtländer un Son in Wien Braunschweig. The Serial number is: 12072

It seems like it's a cemented doublet since there is some lens seperation. It gives a sharp image when the outside world is projected through it unto a wall. and it seems to be around the 300mm mark in it's current state.

150635150636150637150638

[Steven Tribe]

The black finish is a little odd for a lens from this period (after 1868 - "BRaunschweig, Wien"). The obvious answer is it is the front part of the Petzval design for a Landscape lens called the Orthoscope which appeared about 1861. If so, there should be an inner thread at the rear which held the rear cell containing the usual air spaced Petzval pair. I don't know of examples this late - the items I have seen have been in the 7 -8,000 serial number range. The lens could be used as a landscape meniscus as it stands. Was never a common (read: Popular!) lens and the Ross version was just as unpopular!

If you can measure the diameter of the lens, I can tell you what the original lens was like. It could be 53mm perhaps?

The brass barrel has features which are no consistent with other Voigtlander Orthoscopes, so I think the barrel has been extensively altered, probably at the same time that the barrel was lacquered black. The achromat has been mounted in the "original" rear thread, I think. So someone has already adapted it for landscape meniscus use.

[goamules]

On the black color, my estimate is that is a very old patina. I've had many brass lenses, that lost their lacquer, that will turn this shade of very dark brown or black. It's less shiny when that happens, like this one exhibits.

[loman]

Hi Guys. Thanks for the answers. Yes there is an inner thread in the rear to screw into something else.
I've bumped the contrast a bit in the photos to make the text readable, it is quite dull in nature. The paint does seem original, but who knows.
I'll measure the lens in a bit, and get back to you with the exact diameter.

[loman]

Hi Steven. I measured the lens and it is 53mm in diameter :-)

So is it an orthoscope?

Best Regards
Mads

[Steven Tribe]

Thre are really no other possibilities at this period with this type of engraving.

I enclose a brief description auf Deutsch and the sizes made.

This is size no. 3 and you see the "front" lens, the achromat, is 79bzw (53mm in modern measurements!). With a focal length of 23.5" for the combined lenses, yours must be quite a lot more. Coverage will be more than 15x20 and the F value around F16.

There are simple pressure mounts for magic lanterns around the size of the Voigtlander barrel, and tight fitting can be acheived using velvet as a "filler".