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Dual speed focuser and eyepiece extension suggestions?

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#1 Waynerplays

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Posted 13 February 2020 - 01:55 PM

Hello night sky adventurers,

 

I picked up a Skywatcher ST120 achro on a Super Polaris mount for $200 CDN and am finding the focuser definitely needs an upgrade since focus is barely attained at the travel limit and difficult to hone into, so I'm guessing the best solution is to replace with a dual speed focuser and an eyepiece extension.

 

Considering the original purchase price, a Moonlite or other top quality dual speed focuser seems a little overkill, so perhaps something like this GSO, see link, may be more appropriate. I've seen an article outlining steps to eliminate some of its shortcomings, but looking for input on any other possible solutions and recommendations.

 

https://agenaastro.c...speed-86mm.html [agenaastro.com]

 

thank you all 

Wayne



#2 wrnchhead

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Posted 13 February 2020 - 02:03 PM

I have that same focuser, on a scope that cost $90. Worth it. I think the shortcomings of that focuser are a little overblown. It will suit you perfectly .


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#3 junomike

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Posted 13 February 2020 - 02:07 PM

I went with the Linear version as I prefer it over the standard but either will be a nice improvement.



#4 SteveG

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Posted 13 February 2020 - 03:59 PM

I went with the Linear version as I prefer it over the standard but either will be a nice improvement.

Note that the focuser travel with the linear version is only 2". On the standard Crayford linked above, it is 3.1".


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#5 scottmm2012

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Posted 13 February 2020 - 07:51 PM

Lunt has them on sale for $69.95.


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#6 Bean614

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Posted 13 February 2020 - 09:07 PM

So, what were the results when you made the proper adjustments to the original Skywatcher focuser?  You did try adjusting it via the set-screws,  correct?


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#7 Jon Isaacs

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Posted 14 February 2020 - 06:16 AM

So, what were the results when you made the proper adjustments to the original Skywatcher focuser?  You did try adjusting it via the set-screws,  correct?

:waytogo:

 

Disassembling the focuser, cleaning the sticky grease off, adjusting the drawtube and then the pinion assembly preload can result is a much improved focuser. I done more than I can remember. 

 

I often replace the lower pads with bondable Teflon. It helps but just cleaning and adjusting is whats important.  Here is a detailed discussion of my procedure.

 

https://www.cloudyni...d/#entry4616865

 

Jon


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#8 Waynerplays

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Posted 14 February 2020 - 01:58 PM

So, what were the results when you made the proper adjustments to the original Skywatcher focuser?  You did try adjusting it via the set-screws,  correct?

Actually I haven't tried that yet Viking 1, though considering focus is almost beyond the limit of the r&p, in fact I have to pull the eyepiece out a bit and at that point the draw tube is no longer rigid.



#9 Waynerplays

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Posted 14 February 2020 - 02:01 PM

thanks Jon, I'll try that

 

waytogo.gif

 

Disassembling the focuser, cleaning the sticky grease off, adjusting the drawtube and then the pinion assembly preload can result is a much improved focuser. I done more than I can remember. 

 

I often replace the lower pads with bondable Teflon. It helps but just cleaning and adjusting is whats important.  Here is a detailed discussion of my procedure.

 

https://www.cloudyni...d/#entry4616865

 

Jon




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