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DDM160 tube lenght considerations

ddm160 lenght

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#1 lukepower

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Posted 17 November 2013 - 10:34 AM

Hi there,

 

I am a proud user of a DDM85XL; so for a (theorical) project of a few friends and mine we are aiming for a DDM160, as we play with the idea of a VERY large scope sitting on it. We think about a huge Newtonian scope, where the tube would be as long as 2700mm (!), and weight about 250kg. Alright, the weight might be within the limits of the DDM160, but what about the tube lenght? I recall long refractors weighting not so much, but requiring serious mounts just because of their size...

 

Thanks for your comments


Lukas Demetz
------------
www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL


#2 D.Weinzinger

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Posted 26 November 2013 - 12:52 PM

Dear Lukas,

 

for the DDM160, 2700mm is no problem. 

 

Best regards,

Dietmar Weinzinger



#3 lukepower

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Posted 26 November 2013 - 05:21 PM

Die Dietmar,

 

thanks for your answer. Well, how much would be a problem? :) It should be mounted in Namibia and enjoy not only the clear skies, but also crisp winds...

 

Thank you


Lukas Demetz
------------
www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL


#4 zordra

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Posted 03 January 2014 - 07:17 PM

Hi Lukas,

the real problem is, that the Newtonian telescope  f/4,or faster  is always longer than a cassegrain. You need a bigger dome.

But a Cassegrain or a Newton-Telescope   have almost the same weight.

That is the reason, why most of bigger amateur telescopes for photography are Cassegrains. The DDM 160 can carry also e big Newtonian.

 

Best regards

Gerhard



#5 lukepower

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Posted 03 January 2014 - 07:37 PM

Hi Gerhard,

 

thank you for your consideration. Well, I guess we'll end with either a Casssegrain with the camera in prime-focus, or a newtonian scope. Myself, I just mounted a Cassegrain-Newton (interchangeable secondary mirrors) with about 105kg total weight on my DDM85XL and have no issues (besides the really stringent balancing).

 

If I could make a wish to ASA, I would ask for a brake or something like that to lock down the tube once the scope is parked. In my case, once I close the main mirror covers, the little weight shift is enough to make the tube move and hit the roof :P


Lukas Demetz
------------
www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL






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