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How to motorized a helical focuser

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#1 Jeff_Richards

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Posted 25 February 2021 - 11:21 AM

Just curious if there is a way to motorized the helical focuser on my first generation Borg 77ED?



#2 petert913

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Posted 25 February 2021 - 12:00 PM

A lot of people have been trying to figure this out for the WO Redcat as well.  Not sure what solutions have been designed.



#3 Jeff_Richards

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Posted 25 February 2021 - 12:03 PM

Or does anyone know what R&P or Crayford focuser will fit the Borg tube?



#4 michael8554

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Posted 25 February 2021 - 12:14 PM

Camera lenses have helical focusers, you can autofocus a camera lens with a wide rubber drive band on the focus ring and a wide pulley on the focus motor.


Edited by michael8554, 25 February 2021 - 12:14 PM.


#5 TikiTom

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Posted 25 February 2021 - 12:34 PM

Or does anyone know what R&P or Crayford focuser will fit the Borg tube?

   

Here is my Borg 77EDII w/ Borg R&P focuser.

Tried to fit this to my Borg 100 which has a helical, no luck. The focuser is just barely a couple mm's smaller. I can hear it hit the threads, but won't catch...

Attached Thumbnails

  • Borg 77 w-R&P focuser.jpg

Edited by TikiTom, 25 February 2021 - 12:35 PM.


#6 Jeff_Richards

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Posted 25 February 2021 - 12:41 PM

Tom, do you know if the tube is exactly the same for the EDII vs. my original ED? 

 

Thanks!



#7 Seaquel47

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Posted 25 February 2021 - 01:39 PM

I just motorized my Redcat with a ZWO EAF focuser and the kit from deepskydad.com.  It works great with my ASIAir Pro.  You might look there for ideas.


Edited by Seaquel47, 25 February 2021 - 01:40 PM.

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#8 TikiTom

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Posted 25 February 2021 - 01:40 PM

Tom, do you know if the tube is exactly the same for the EDII vs. my original ED? 

 

Thanks!

Jeff--

these parts fit interchangeably:

Borg 76ach objective 

Borg #7875 helical focuser

 

So I would would think it's all the same. I just can't imagine that they would change the tubes by only 2-3 millimeters going from series EDI to series EDII.

I will have to look at the focuser pieces again. Maybe there is a spacer or something that fits in. Borgs are too modular to be just a pinch smaller (or bigger)? 

 

The focuser on this 100 doesn't have a part #, maybe I'll find time to unscrew a bunch of parts from this 100 and see what fits which...

Attached Thumbnails

  • Borg #7857 focuser.jpg
  • Borg 76 Objective.jpg
  • Borg100 + Borg60ED.jpg

Edited by TikiTom, 25 February 2021 - 01:42 PM.


#9 Jeff_Richards

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Posted 25 February 2021 - 02:00 PM

Appreciate all the input! I'm thinking one of the belt drive systems might work (Pegasus would be ideal since I have ultimate V2 box).


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#10 Jeff_Richards

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Posted 25 February 2021 - 04:02 PM

Why does Borg have to use a M68.8 thread on the OTA? If they had just used a standard M68 or M57 that would make life much easier (finding a focuser that could be used). Love the Borg modularity but hate the custom sizes.



#11 davidparks

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Posted 26 February 2021 - 10:09 AM

For the Redcat 51, but may inspire.

 

WO Redcat 51 All ZWO’d Up


#12 Jeff_Richards

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Posted 26 February 2021 - 11:15 AM

For the Redcat 51, but may inspire.

 

Nice, looks like Pegasus also has a similar set up. I already have their ultimate V2 box so might attempt that route.



#13 Jeff_Richards

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Posted 28 February 2021 - 08:25 AM

Well I ordered the Pegasus focus motor with the timing belt. Fingers crossed I can get it to work. waytogo.gif


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#14 TikiTom

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Posted 28 February 2021 - 12:10 PM

Well I ordered the Pegasus focus motor with the timing belt. Fingers crossed I can get it to work. waytogo.gif

Can you post a report back here once you have it and get it installed?

 

Thanks!


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#15 Jeff_Richards

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Posted 28 February 2021 - 12:52 PM

Will do. Hopefully by next weekend but if I end up having to get another plate to mount it then might take a bit longer...either way I will provide updates.


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#16 Jeff_Richards

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Posted 02 March 2021 - 07:40 AM

Well stupid me, it's been quite some time since I've had my Borg mounted and in use. I should have checked it before ordering the motor. As it turns out, the helical focuser is not stationary so the knurled part travels along the focuser's axis as it is turned so a belt drive won't work. So now I'm stuck replacing the focuser. I wanted to get the Baader but it won't fit the very odd sized drawtube threads on the Borg (68.8/.75). 

 

I guess the only option is going to be the Borg R&P focuser if it's available.


Edited by Jeff_Richards, 02 March 2021 - 11:59 AM.


#17 Jeff_Richards

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Posted 02 March 2021 - 07:43 AM

Wish I knew the outside thread size of the Borg drawtube...maybe there would be a "standard" sized adapter to go from that size to the 68/1 of the Baader.




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