Dallmeyer Radial Drive - research needed on transitional optics

[goamules]

I had to buy this Dallmeyer telescope mostly because I've never seen one. I know the history was that J.H. Dallmeyer married Andrew Ross' daughter, and inherited 1/3 of the Ross business - the telescope part. He made telescopes for a period, but concentrated on camera lenses and patented several new designs. But I've never seen one of his library telescopes. Now the research begins. How early is this telescope? How many were made? The engraving on the stand appears to be the regular script. On the rear of the barrel is block lettering, common on early telescopes from the early 19th century on. I hope you enjoy this somewhat off topic post, as we learn more about this amazing lens maker.

I love getting packages, especially very heavy, wooden packages with old fashioned hinges and latches.

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Opening the box reveals gleaming golden treasure. The most famous 19th century name in lenses is engraved around the rear, as well as London.

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First, let me unpack and assemble the stand. It weighs many more times than the telescope (why did tripod makers forget this important attribute to stability?).

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[goamules]

Yes, that's one substantial stand, around 20 pounds. The base appears to rotate, but I have not experimented with it yet. Let's just get that telescope on it!

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Here is the radial focus knob. In all respects, I can see classic Dallmeyer motifs that appear on lenses like the 3A and 3B in such demand today. The flat, serrated knurling on the knobs is just one example. The threads are all precise, and the lacquer is a golden yellow with just a hint of red-orange. Not the more orange yellow of early French lacquers. Some of the brass has a more copper color, perhaps a different alloy for more critical parts like the locknut for the telescope angle setting.

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[goamules]

The ocular tube got dented in shipping, so I'm still reforming the inner tube that goes into the rear. Clear skys in Arizona now that it's winter, I'll have to be patient for the first viewing! The lenses were dirty, but fortunately all threads are easily unscrewed, and I've cleaned each part of the rear occular eyepiece. And there are a bunch of them, it's a very complex sequence of lenses. The front objective looks fine. Stay tuned, as I try to carefully get the eyepiece back in round to install, and take a first peek through glass that was quite probably ground by JH Dallmeyer himself!

[Jim C.]

Sweet telescope Garrett !
Guess this would be Vintage Telescope Porn, rather than Vintage Lens Porn. ;)

[Steven Tribe]

Absolutely a relevant topic! Not only were many early makers into both telescopes and photographic optics but there is a lot of similarity between the object lens design and the basic achromat used in landscape lenses and the front lens of the Petzval.
Websters database on instrument makers mentions a catalogue issued "as late as 1865". Dallmeyer was so busy with the RR and Petzval redesign that I doubt he continued much beyond that date - it could have "while stocks last" already by 1865. This is obviously a superb piece of brass, engineering and optics. Unfortunately, the telescopes made by Ross (at least the more standard models), seem to be indistinguishable from other makers.
I have had periods when I have bought (non-library models) Georgian and Victorian telescopes and have been delighted with the easy threads (all hand-made) and perfect glass. The only problem are the larger 'scopes (above 30") which often have difficult object lens threads due to multi impact damage and turned brass lens capture. Glass is always good.

[goamules]

Thanks Steven. I'm guessing 1860s too, because other than Dallmeyer "getting a start" in telescopes, I think he got so much business from camera optics, he concentrated there early. I've contacted a few friend/collectors at the University Optical Science Museum, and may take it by for an appraisal. It came from the estate of a big science instrument collector back East. Still working to get the eyepiece round enough to insert...working slow and carefully.

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[Steven Tribe]

I have looked through some of the recent auction sales (found yours too!).
All seem to be the "Library type" and there are not many around.
One has a very clear date as it was a presentation item - 1863.

[goamules]

Excellent! PM me the link to that one for my records. Yeah, they guy had tried to sell this for the going rate for "known maker" telescopes, but for some reason no one was biting on this one. I talked to him and was convinced it has important optical history, so bought it.

[goamules]

Thanks for sending the links to comparison telescopes Steven. Here it is in all it's glory, I finally got the eyepiece on (and hope one day it will come off if I need it to), and it focuses very sharply from 15 yards to infinity. I'll look at the moon and stars tonight, but it's a sharp scope. I use a lot of range scopes in target shooting, and this one would put some of them to shame!

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[rosha80]

Good day!
I have the telescope HH DELLAMAYER. Similar to yours. In the worst condition.
have questions on it. contact me by email

[goamules]

I missed this post. But still have the telescope, which I use from time to time. Have seen few, if any, Dallmeyer library telescopes in the intervening 6 years.