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"Low maintenance" 8" newt?

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#1 bokemon

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Posted 19 September 2020 - 06:10 AM

Hello folks,

I am looking for an 8" F/4 Newtonian for imaging use that can survive a bumpy car drive over the hills without the collimation going totally out of whack. 

(Yes, I will try to pad it well)  Also the weight of the OTA by itself should be on the lighter side, maybe less than 18 lbs?  Finally, focuser and secondary large enough for APS-C sensor.  (might require 2.5" focuser?)

The only ones which I have heard are "low maintenance" are:

TS ONTC carbon fiber w/ 3" focuser- weight approx 15 lbs

Vixen R200SS - weight approx 15 lbs

Any others?



#2 mikefulb

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Posted 19 September 2020 - 07:11 AM

I think my TS ONTC 8 inch f/4 weighs more than that but I have dual rails on it - a D plate plus rings will add a few lbs.

 

It holds collimation extremely well but I wouldn't go so far as to say I haven't had to tweak it a little after a long drive from time to time.


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#3 bokemon

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Posted 19 September 2020 - 07:54 AM

Hmm, TS said "The weight including dovetail and rings is roughly 7kg".



#4 sg6

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Posted 19 September 2020 - 08:55 AM

I would doubt it owing to the nature of a newtonian and especially if you add if fast, imaging and a car journey.

 

At f/4 I would say most will check the scope at almost every time it is used.

 

For imaging you almost have to check one everytime as losing a whole nights image collection owing to even a small loss of collimation is not a good idea. So you spend 10 minutes checking it automatically, just to be safe.

 

Taking an f/4 imaging newtonian for a car ride means a good chance of something not being right at the end of the trip.



#5 mikefulb

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Posted 19 September 2020 - 10:06 AM

The thing to remember is if it is a well constructed Newtonian tweaking it up is a quick process usually when you have gotten some experience and know how the scope behaves.  I'm talking tiny fractions of a turn of a screw corrections, not starting all over with a sight tube and getting the secondary offset correct level of work.

 

I'm rather generous in my acceptance of some image imperfections and I don't pixel peep the corners much any more so I find throwing in my tublug and tweaking screws for 2 or 3 minutes gets things close enough for me.  I don't look at it through an autocollimator because I'm sure I would spend even more time getting it perfect and stressing over it, but have learned life is short and I get images that don't embarrass me so that is just fine.  :)

 

YMMV of course!



#6 SeattleScott

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Posted 19 September 2020 - 11:07 AM

Vixen R200


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