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Orion RC 8 inch

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#1 jaimac

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Posted 07 July 2020 - 10:13 AM

Hi,

How is the Orion RC 8 inch for viewing and photography? I want to get sell the Williams Optics 72mm Megrez as I can't get the flattener and Discovery 6" Dob.

 

https://www.telescop...60/p/113910.uts
 

 

- Jai



#2 bobzeq25

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Posted 07 July 2020 - 12:32 PM

It's more an imaging scope than a visual scope.  It can do visual, the large central obstruction will reduce contrast some.  Not a problem in imaging, you fix it in postprocessing.

 

The inexpensive RCs present a dilemma for imaging.  The optics are superb, the mechanicals - not so much.  And the RC design is particularly sensitive to mechanical errors.

 

The upshot is collimation is difficult (the two complex mirrors interact), and that people often spend a lot of money on the seemingly inexpensive scope addressing various issues.

 

My 6RC was delivered in poor collimation (the diffraction spikes were doubled).  That took weeks to research and fix.  By the time I stopped using the scope, I had $1200 in the "$400" scope.

 

Compare to an SCT.  The virtue of the SCT design is that you can manufacture pretty good scopes inexpensively.  The design is not perfect (the Edge versions are better), but it's robust.

 

Here's what it takes to make a really good RC.  Scroll down.

 

http://www.knaeble-eng.com/

 

$$$

 

Bottom line.  Some people like these, some people hate them (mostly collimation issues).  I thought mine was OK after I got it collimated, but it developed focuser issues.  Many people replace the focuser, Moonlites are popular.  I replaced the focuser with a 3.7 inch high quality rack and pinion.  It came attached to a 130mm F7 refractor.  <smile>


Edited by bobzeq25, 07 July 2020 - 12:35 PM.


#3 jaimac

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Posted 07 July 2020 - 11:00 PM

I saw reviews about collimation. The reflector itself is a collimation headache for me. I guess, I will stick to refractors. Thank you for the clarification. 


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