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Which Crayford Focuser for SCT ?

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3 replies to this topic

#1 carlm01

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Posted 24 August 2019 - 09:50 PM

Looking to add a crayford focuser to my 6"SCT  for visual use with a bino,, I'm not looking to spend a fortune but something decent ,As always any opinions are greatly appreciated.... Thanks  



#2 DuncanM

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Posted 24 August 2019 - 11:01 PM

I've had good luck with JMI crayfords. 



#3 AZ Maverick

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Posted 24 August 2019 - 11:19 PM

I'm spending a fortune and going with a Moonlight focuser on my 9.25" SCT. blush.gif

At full focal length it is almost impossible to focus that thing manually and for photography I'm sick and tired of the time spent trying to hit focus.



#4 mclewis1

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Posted 25 August 2019 - 08:04 AM

Looking to add a crayford focuser to my 6"SCT  for visual use with a bino,, I'm not looking to spend a fortune but something decent ,As always any opinions are greatly appreciated.... Thanks  

There are a lot of things to consider and especially on the smaller C6.

 

- If your scope is fork mounted the external crayford is going to add a lot of weight to a very light weight scope making balancing a problem. There is also the question about fork base clearance.

 

- You have to still be able to use the stock focuser knob (unless you restrict the scope to one very specfic configuration) and an external focuser is going to get very close or possibly contact the knob. Things are very tight on the rear cell of the C6 ... even just a 2in diagonal can be a problem.

 

- Adding an external focuser adds 75 to 100mm of spacing and that is going to lengthen your focal length substantially (multiply the extra physical spacing by at least 3x). With a binoviewer and external focuser your C6 is going from an f10 to about and f14 scope. 




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