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Reinfelder & Hertel Munchin 75mm Optics Set?

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#1 Tom Duncan

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Posted 02 May 2017 - 10:13 AM

Bought a couple of boxes of optical flotsam the other day, found these two pieces of interest.

 

The 75mm objective doublet set in a brass cell is labeled 'Reinfelder & Hertel', a name with which I am familiar as being a high-grade telescope manufacturer of wood and brass bodied telescopes in the late 1800s. While the glass is crispy clear to the naked eye upon closer inspection some schmutz can be seen between the elements and there are some scratches on the outer surfaces.  

 

The other piece has no ID markings on it but after doing a Google Image search on Reinfelder & Hertel I found quite a few scopes that look to have the same eyepiece/end tube arrangement. The finish, wear and overal patina is the same as the cell so I'm pretty certain this is the back half of the R&H optical train. Can anyone confirm that? 

 

I taped the objective cell to a window and looked through the eyepiece/end tube hand-held and I could roughly see an image come to focus but this was an admittedly crude test and the target was such that I couldn't ascertain if there was any image orientation correction.

 

The tube itself has at least two elements, not including the eyepiece noted below, so this appears to be at least a four-element design. Is this a common arrangement with R&H scopes?

 

The eyepiece/end tube is a bit odd in that it appears to have an eyepiece trapped behind the bezel (last photo). Makes for awful eye relief. 

 

Thanks in advance for your inputs. 

 

Tom Duncan 

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#2 Piggyback

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Posted 02 May 2017 - 12:48 PM

Very nice lens and congratulations on a super-find. You got a jewel there. Optical company Reinfelder und Hertel was the leading German manufacturer of quality telescopes in the late 1800's. In 1857 Gottlieb Reinfelder and Wilhelm Hertel were employed as optical craftsmen by the famous C.A. von Steinheil optical works in Munich. In 1867 they founded the Reinfelder and Hertel optical works. Hertel passed away in 1893 and Reinfelder led the company to also make geodetic instruments. Your objective probably stems from the late 1800's. Reinfelder died of Diabetes in 1898. The biggest objective he made was a 14 inch (352mm) achromat for the observatory in Königsberg. Your brass extension tube seems to be an "Erdansatz". This device acted to deliver an upright image for earth based observations, much like a Porro-prism.


Edited by Piggyback, 02 May 2017 - 03:36 PM.

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#3 Piggyback

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Posted 02 May 2017 - 03:44 PM

Tom, I believe your lens is an achromat and as such it should be equipped with spacers between the lenses. I can't see them on your pic.



#4 Tom Duncan

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Posted 02 May 2017 - 09:50 PM

I'll test this stuff a bit more when I get time. I'll see if the objective throws and image of my window on the wall which should indicated if the doublet stands on its own as well as approximate focal length, plus I'll try to ascertain if the tube is an image erector.

 

Lots of Google images for R&H show scopes with a similar looking extension/tube, but no closeups I've been able to find. 

 

Definately a doublet (and likely an achromat but no way to tell for sure until I can star or bench test it but I think that's a safe bet), no spacers, the two pieces of glass rest against each other at their edges, about 1/16" or so between them in the middle. 

 

I took the glass out of the cell, I figured if it wanted to come out it would and it did without issue. I marked the relative positions of course. 

 

I found writing on the edges which I photographed and have attached. Note I increased the contrast massively to make it legible, it's actually in light pencil. Can anyone interpret it? 

 

Tom 

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Edited by Tom Duncan, 02 May 2017 - 09:51 PM.

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#5 Piggyback

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Posted 03 May 2017 - 01:13 AM

The writing on the edge says lens was cleaned February 10, 1921 by optician Paul Schulz. I am not sure about the last word, though. Should be the name of a german town but I simply can't figure it out.

 

I believe yours is a Steinheil airspaced achromat. When cleaning the lenses optician Schulz may have seemed spacers an unnecessary oddity or these were lost at a later time. Shine a strong light on the lens and use a magnifying glas to check for traces of residue from the spacers. If only your lens could talk. It has been through the sinking of Titanic, WW1, WW2. A true survivor! You are now the latest in a long list of caretakers. Bring that puppy back to life...


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#6 Tom Duncan

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Posted 03 May 2017 - 12:52 PM

There does appear to be glue remnants on the front element in the typical three places where small spacers commonly are in todays doublet designs so you are likely correct about that. So that type of build was done way back then, with spacers? 

 

I think the second element may be in backwards as there is a glue remnant on its edge just like the ones on the front element, however it is on the outside surface as it was assembled when I got it. There are three pressure points of the metal retaining ring but they are longer and don't match the glue remnant footprint. That being said I re-assembled the elements in the cell the way I got them. I checked the projected image on my wall from a window and it seems kinda sharp but I have no way to check it further. A new owner will want to fiddle with the element positions, fortunately it being easily done.

 

The distance between the cell and the semi-focused image on the wall (hand held so a bit shaky) is about 45", admittedly a crude measurement. Subject was not at infinity but a tree about 100 yards away so again, a crude estimation. So my guess is this is a 75mm f15? Does that jive with known R&H scopes? 

 

Tom  



#7 Tom Duncan

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Posted 03 May 2017 - 01:02 PM

I have some questions about the extra tube.

 

Referring to the photo attached, is the eyepiece supposed to go inside the tube or was that just a convenient place to put it by someone. It doesn't fit very positively and the eye relief is non-existant looking through the tube with the EP inside it. There is no writing on the EP that I can find. The eye relief is the typical old school very short but not unlike short Orthos. 

 

Is this an actual eyepiece? Diameter of the tube is the standard .965" (USA). I'm going to try it tonight in an attempt to establish its focal length and FOV. 

 

And what would the threads inside the tube (you can see them in the photo) be for? The eye bezel goes on the outer threads. 

 

Tom 

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#8 bremms

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Posted 03 May 2017 - 01:50 PM

I'll test this stuff a bit more when I get time. I'll see if the objective throws and image of my window on the wall which should indicated if the doublet stands on its own as well as approximate focal length, plus I'll try to ascertain if the tube is an image erector.

 

Lots of Google images for R&H show scopes with a similar looking extension/tube, but no closeups I've been able to find. 

 

Definately a doublet (and likely an achromat but no way to tell for sure until I can star or bench test it but I think that's a safe bet), no spacers, the two pieces of glass rest against each other at their edges, about 1/16" or so between them in the middle. 

 

I took the glass out of the cell, I figured if it wanted to come out it would and it did without issue. I marked the relative positions of course. 

 

I found writing on the edges which I photographed and have attached. Note I increased the contrast massively to make it legible, it's actually in light pencil. Can anyone interpret it? 

 

 

Tom,  If there is that much gap in the center between the elements, my guess is the crown is reversed. The Steiheil design used very similar curves on the inner surfaces with a thin foil spacer. The flint is forward in a Steinheil, but many lenses were flipped in their cells with resultant bad images. Flipping the crown around may have been done to try and fix the issue. Just a guess..



#9 Tom Duncan

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Posted 03 May 2017 - 03:09 PM

Checked out the secondary tube again with the cell taped to a window and it is indeed an image erector. Still not completely convinced it's part of objective set though as I was doing this hand held and it was all a bit shaky. 

 

I also reversed the seconday element and reassembled the objective. The thicker element is out front, thinner at the back. Is that the Steinheil way? 

 

Tom 



#10 bremms

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Posted 03 May 2017 - 08:29 PM

Checked out the secondary tube again with the cell taped to a window and it is indeed an image erector. Still not completely convinced it's part of objective set though as I was doing this hand held and it was all a bit shaky. 

 

I also reversed the seconday element and reassembled the objective. The thicker element is out front, thinner at the back. Is that the Steinheil way? 

 

Tom 

Yes, but you might want to check with the ATS yahoo group. The company is related to Steinheil, so I imagine that's the type of objective. I could be wrong, but it makes sense.



#11 jring

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Posted 04 May 2017 - 09:42 AM

Hi,

 

some history on the company has already been correctly given, I found some info on a german forum that the company ceased operations sometimes around 1920.

 

http://www.astrotref...&TOPIC_ID=68954

 

This fits the writing on the side of the objective lenses which certainly start like this:

 

genehmigt 10.2.21. Optiker <some name>

 

approved Feb 10th 21 optician <some name>

 

Edit: seems sb. was faster with the writing - and more correct too... should have been reading the thread...

 

Regards,

 

Joachim


Edited by jring, 04 May 2017 - 09:50 AM.


#12 Tom Duncan

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Posted 04 May 2017 - 10:25 AM

Any input on the eyepiece and its found location? 

 

Tom 



#13 Piggyback

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Posted 04 May 2017 - 11:22 AM

Could you please post detail shots of your image corrector. It would be helpful to see what lenses are inside that long barrel.



#14 Tom Duncan

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Posted 04 May 2017 - 01:04 PM

I've attached photos of the tube. 

 

First is overall, it's about 8" long, threaded both ends, one for the eye bezel, the other to attach to the scope drawtube I'm assuming. 

 

There appear to be three elements (assuming all three glass pieces are singlets), two are contained in a module that threads into the tube as shown in the fourth photo. There is a very small field stop/baffle in the module between the elements. 

 

Fifth and last photo shows the third element that is inside the tube at the eye end with yet another field stop/baffle, with the eye bezel removed. There is a notch that appears to be factory made in the threads on the eye bezel end, you can see it at 12 o'clock. 

 

For some reason the glass is all very clear, usually old glass like this is covered in schmutz. 

 

Tom 

 

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#15 Bomber Bob

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Posted 04 May 2017 - 05:28 PM

Looks very similar to one of two that I have -- the one that came with the "English" astronomical eyepiece set.  I haven't tried either with my Mogey because the threads don't match it.  The English one accepts any of the eyepieces that came in the set.  It has a two element pair at the sky end, and two baffles inside the tube.  The other erector is shorter & plainer.  The eyepieces are smaller barreled, and thread into the end rather than over it, THEN one of two caps thread over with either a solar filter or an empty slot.  These eyepieces were in the best condition.



#16 Piggyback

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Posted 05 May 2017 - 03:48 PM

Your pic shows an empty eyepiece holder. There should be a total of four lenses in two separate tube assemblies that mount inside your Erdansatz. What Bomber Bob says, there is a two element pair at the sky end and another pair at the eyepiece end.



#17 Piggyback

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Posted 05 May 2017 - 03:57 PM

Here is a pic of a typical Erdansatz. Hope this helps.

 

 

Erdansatz_red.jpg


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#18 Tom Duncan

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Posted 05 May 2017 - 05:31 PM

What does "Erdansatz" translate to? Google translate was no help. 

 

So what I have is the tube with one internal two-lens tube assembly and one eye bezel, missing one internal tube assembly, right? 

 

So the apparent EP that I got that was inside the eye end of the tube is just that, an EP, and not the proper internal tube assembly? 

 

Tom 



#19 Piggyback

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Posted 06 May 2017 - 12:28 AM

What does "Erdansatz" translate to? Google translate was no help. 

 

So what I have is the tube with one internal two-lens tube assembly and one eye bezel, missing one internal tube assembly, right? 

 

So the apparent EP that I got that was inside the eye end of the tube is just that, an EP, and not the proper internal tube assembly? 

 

Tom 

 

"Erdansatz" meaning "earth attachment" is a term that was commonly used for tubular image correcting devices. To my understanding these were later replaced bei cheaper to make porro prism attachments that served the same purpose. Your best bet to inquire about a complete Erdansatz assembly might be to contact Xavier.


Edited by Piggyback, 06 May 2017 - 12:43 AM.

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#20 Tom Duncan

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Posted 06 May 2017 - 06:46 AM

OK, thanks for the explanation of Erdansatz. So an upright image for terrestrial ('earth') use. 

 

I've contacted Xavier regarding this thread. 

 

Thanks all. 

 

Tom 



#21 Dan /schechter

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Posted 07 May 2017 - 04:14 PM

Hi Tom,

 

I agree with those who say your eyepiece is a terrestrial eyepiece that produces an erect image. I have one that came with a 3" Clark telescope. I am not 100% sure it was made by the Clark Corporation, but it certainly fits properly. It consists of two pairs of eyepieces. The first eyepiece slips into the end of the tube just like yours does. An eye cap threads onto the tube over the eyepiece like yours does to secure it in place.

 

If you look at the bottom right picture of the first group you posted, the tube shows end threads on the outside, but there is a gap or notch ( for lack of a better word) in the end. My terrestrial eyepiece has the same notch. It provides access to a tube that slips inside the pictured tube and holds the second eyepiece of the pair. I see the notch in yours, but do not see the secondary narrower tube the notch was made to provide access to.

 

My main/outside tube is about 16 1/4" long. The secondary tube places the second eyepiece approximately midway in the outside tube. The main tube is so long because it has to be extended quite a distance behind the draw tube to come to focus. Yours might night not have come to focus because it was too close to your objective.

 

Hope this makes sense and helps,

Dan




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