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Astro-Berlin Telastan 2000/10
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PostPosted: Thu Oct 30, 2014 7:55 am    Post subject: Astro-Berlin Telastan 2000/10 Reply with quote

For all colleagues out there who like stovepipe-style long-focus lenses, I finally managed to get hold of a 58-yr old pic showing a copy of the famous-but-impossible-to-locate Astro Berlin Telastan 2000mm f/10 lens, enjoy:



PostPosted: Thu Oct 30, 2014 8:04 am    Post subject: Reply with quote

Thanks for the picture!
Nice hood Smile


PostPosted: Thu Oct 30, 2014 9:00 am    Post subject: Reply with quote

Don't do that at home. He's pointing it more or less straight to the Sun...


PostPosted: Thu Oct 30, 2014 11:04 am    Post subject: Reply with quote

f/10 2000mm... OMG! Very Happy
Thanks for sharing.


Gamera wrote:
Don't do that at home. He's pointing it more or less straight to the Sun...

For the angle of shading and lens, NOT really! (He is pointing to top and right of the sun) Rolling Eyes

More intriguing is where/how is he sitting Laughing


PostPosted: Thu Oct 30, 2014 4:19 pm    Post subject: Reply with quote

That's a nice picture of that rare lens!
Thanks for sharing
I wonder, if you have the rights for it and could probably allow me to add it to my Astro-site?

Klaus

http://www.exaklaus.de/astro.htm


PostPosted: Fri Oct 31, 2014 7:20 am    Post subject: Reply with quote

exaklaus wrote:
That's a nice picture of that rare lens!
Thanks for sharing
I wonder, if you have the rights for it and could probably allow me to add it to my Astro-site?

Klaus

http://www.exaklaus.de/astro.htm


I'm glad you asked; please, by all means do add this to your excellent site, no worries about the rights since I'm the current owner of the pic. I'm sending you the relevant files by e-mail.


PostPosted: Fri Oct 31, 2014 9:45 am    Post subject: Reply with quote

SVP wrote:
exaklaus wrote:
That's a nice picture of that rare lens!
Thanks for sharing
I wonder, if you have the rights for it and could probably allow me to add it to my Astro-site?

Klaus

http://www.exaklaus.de/astro.htm


I'm glad you asked; please, by all means do add this to your excellent site, no worries about the rights since I'm the current owner of the pic. I'm sending you the relevant files by e-mail.


That's absolutly great
Klaus


PostPosted: Fri Oct 31, 2014 9:56 am    Post subject: Reply with quote

Done!


PostPosted: Fri Oct 31, 2014 12:20 pm    Post subject: Reply with quote

Impressive! And I used to think my 640mm f4,5 version was big.. Maybe if I build a lens tube for my 800mm f/5 astro glass I´ll get something approaching this again.


PostPosted: Sat Nov 01, 2014 12:33 am    Post subject: Reply with quote

Damn, SVP, I thought you had them all.
Or it's the only one missing from your collection?


PostPosted: Sat Nov 01, 2014 7:57 pm    Post subject: Reply with quote

Himself wrote:
Damn, SVP, I thought you had them all.
Or it's the only one missing from your collection?


Yeap, still missing this one; after many-many years of searching I only managed to get hold of the pic...


PostPosted: Sat Nov 01, 2014 10:25 pm    Post subject: Reply with quote

This lens is very impressive, at least in the picture. However, if the intended application was still or cine photography, this lens does not make much sense, technically speaking.

Telephoto lenses made with conventional optical glasses suffer from longitudinal chromatic aberration. The secondary spectrum (difference in focal length for green and blue-red) is approximately 0.1% of the focal length. The secondary spectrum of a 400mm lens is approximately 0.4mm, which means that the lens has to be stopped-down to F11 to achieve a truly sharp image. By this logic, the Astro-Berlin Telastan 2000/10 had a secondary spectrum of about 2mm, so wide-open performance should be extremely poor, and the Astro-Berlin Telastan had to be stopped-down to F45 to circumvent the longitudinal chromatic aberration. Sadly an aperture F45 would make the resolution to be very low due to diffraction. In summary, the Berlin Telestan 2000/10 was an impractical project for its time.

Today, a high-performance telephoto lens with focal length of 2000mm and aperture F10 can be built because very low dispersion optical glasses are readily available. However, at the time the Astro-Berlin Telastan 2000/10 was made, these glasses were not available.

Probably only a few (one?) prototypes were made for marketing purposes. I suspect the performance of the real lens was so poor that the prototype(s) was(were) destroyed soon after. Maybe that explains why the Astro-Berlin Telastan 2000/10 is so hard (impossible?) to be found today.


PostPosted: Sat Nov 01, 2014 11:02 pm    Post subject: Reply with quote

It doesn't matter Gerald. All those technicalities are not important.
It's about having the thing. Getting the last piece of the puzzle.


PostPosted: Sat Nov 01, 2014 11:59 pm    Post subject: Reply with quote

Shocked That's big! Thanks for sharing the photo!


PostPosted: Sun Nov 02, 2014 12:34 am    Post subject: Reply with quote

Thanks for sharing, some lovely workmanship in that tripod

Found this on ebay, very strange setup Click here to see on Ebay


Last edited by Tervueren on Sun Nov 02, 2014 12:48 am; edited 1 time in total


PostPosted: Sun Nov 02, 2014 12:44 am    Post subject: Reply with quote

Himself wrote:
All those technicalities are not important.
It's about having the thing. Getting the last piece of the puzzle.

Obviously, you are not interested in, as you said, "those technicalities", but only in "having the things". OK, that is your right.

Other people, including myself, have great interest in the technical aspects of lenses because, among other things, the technical aspects could explain why the Astro-Berlin Telestan 2000/10 is a mirage today.

The Celestron C8 has more or less the same focal length and aperture of the Astro-Berlin Telestan 2000/10. Thus, they are more or less equivalent lenses, but the performance of the Celestron C8 certainly is much better because the Celestron is virtually free of chromatic aberration. As for the practicality of both lenses, just compare the picture below with the one presented by the OP.



Picture extracted from this site: http://www.scopereviews.com/C8History.html


PostPosted: Sun Nov 02, 2014 4:41 am    Post subject: Reply with quote

SVP wrote:
Himself wrote:
Damn, SVP, I thought you had them all.
Or it's the only one missing from your collection?


Yeap, still missing this one; after many-many years of searching I only managed to get hold of the pic...


Wonderful Spyros, thanks for sharing!


PostPosted: Sun Nov 02, 2014 5:33 pm    Post subject: Reply with quote

@Gerald: No doubt you're right, maybe that's why Astro-Berlin also developed a somewhat slower APO-Telastan 2000/11 (similarly impossible to find, I'm afraid).
Anyway, it is my understanding that the longer lenses of that period (Astro-Berlin, TEWE-Berlin and the like) were mainly cine lenses, mostly used for b&w filming of nuclear testing efforts and missile launches at safe distances from the proving grounds; for that purpose they were quite capable.


PostPosted: Tue Nov 04, 2014 3:35 am    Post subject: Reply with quote

Gerald wrote:
By this logic, the Astro-Berlin Telastan 2000/10 had a secondary spectrum of about 2mm, so wide-open performance should be extremely poor, and the Astro-Berlin Telastan had to be stopped-down to F45 to circumvent the longitudinal chromatic aberration.

SVP wrote:
Anyway, it is my understanding that the longer lenses of that period (Astro-Berlin, TEWE-Berlin and the like) were mainly cine lenses, mostly used for b&w filming of nuclear testing efforts and missile launches at safe distances from the proving grounds; for that purpose they were quite capable.

And for filming a nuclear blast, you would have enough light to close down the aperture to F/45 anyway...

Cheers!

Abbazz


PostPosted: Thu Nov 26, 2015 10:27 am    Post subject: Reply with quote

I just want to mention an important difference between the Celestron and the Telastan :

The Telastan 10/2000 and the Apo-Telastan 11/2000 will give you an image circle of 154 mm (if you have
managed to get one).
The Celestron is some kind of Astro - junk ( for me . . . . ), barely covering a full frame sensor.

By the way: if you found more than one of the 10/2000 or 11/2000, please let me know.
I am looking for them the last 30 years . . .

Thomas


PostPosted: Thu Nov 26, 2015 10:45 am    Post subject: Reply with quote

Edited

Last edited by bernhardas on Tue May 10, 2016 4:48 pm; edited 1 time in total


PostPosted: Thu Nov 26, 2015 1:18 pm    Post subject: Re: Astro-Berlin Telastan 2000/10 Reply with quote

Not very good for selfies

Smile

SVP wrote:
For all colleagues out there who like stovepipe-style long-focus lenses, I finally managed to get hold of a 58-yr old pic showing a copy of the famous-but-impossible-to-locate Astro Berlin Telastan 2000mm f/10 lens, enjoy:



PostPosted: Thu Nov 26, 2015 4:27 pm    Post subject: Re: Astro-Berlin Telastan 2000/10 Reply with quote

wolan wrote:
Not very good for selfies

Smile

SVP wrote:
For all colleagues out there who like stovepipe-style long-focus lenses, I finally managed to get hold of a 58-yr old pic showing a copy of the famous-but-impossible-to-locate Astro Berlin Telastan 2000mm f/10 lens, enjoy:


Depends how long your selfie stick is Wink


PostPosted: Thu Nov 26, 2015 4:32 pm    Post subject: Reply with quote

Whoo Turtle Like Dog


PostPosted: Thu Nov 26, 2015 5:10 pm    Post subject: Re: Astro-Berlin Telastan 2000/10 Reply with quote

kds315* wrote:
wolan wrote:
Not very good for selfies

Smile

SVP wrote:
For all colleagues out there who like stovepipe-style long-focus lenses, I finally managed to get hold of a 58-yr old pic showing a copy of the famous-but-impossible-to-locate Astro Berlin Telastan 2000mm f/10 lens, enjoy:


Depends how long your selfie stick is Wink


Seriously, I am afraid the minimal focusing distance is such, that you need to jump on the next train to get far enough. Of course the shutter speed must be set accordingly.
Smile

Cheers.