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Astrotech 80 EDT course focus knob removal

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#1 Carl Wright

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Posted 05 February 2020 - 03:20 PM

I am trying to install a motorized focuser on my AT80EDT. The Course knob will not come off after removing the small set screw. 



#2 rgreenberg2000

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Posted 05 February 2020 - 04:31 PM

Carl, I'm pretty sure that it's the same setup as on my Z61 and there are TWO screws on that coarse knob.  Once you remove the first, you may need to slowly rotate the knob to center the second one in the access hole.  Give it a shot!

 

Rich


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#3 Drewalvey

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Posted 24 November 2020 - 07:47 PM

Did you ever figure it out? I have the same scope and trying to install the ZWO EAF and cannot get the knob off.

#4 wxcloud

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Posted 24 November 2020 - 09:10 PM

As a new AT80EDT looking to add a Pegasus focus cube to my rig, I'm curious about how to go about removing the knob also.

#5 wxcloud

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Posted 26 November 2020 - 04:40 PM

I found a couple hex (Allen key) style set screws on the knob, presumably connecting to the focus shaft. In about a 12 and 2 position It's a pretty tight fit. I got the hex head in that would fit and tried to turn one of the two set (grub) screws. They wouldn't budge and the Allen key slipped. Hopefully things didn't strip.

I didn't mess with the little grub screws on the actual scope focus assembly.

Lock tight? Allen wrench a hair too small? Screws not meant to be removed? Wrong grub screws? Really afraid of breaking this thing. Haven't found much info on google to remove the knob :(

#6 wxcloud

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Posted 26 November 2020 - 05:09 PM

Here is a crummy pic of the two grub screws of what I believe are holding the knob onto the focus mechanism. The black knob is up in the picture the suspected grin screws just below. I'm not messing with the silver ones on the scopes body.

Edit: finally just broke down and sent an email to astronomics. Hopefully they can help :)

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Edited by wxcloud, 26 November 2020 - 05:23 PM.


#7 wxcloud

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Posted 27 November 2020 - 03:44 PM

Mike got back to me very quickly! Here is what he said:

On the bottom of focuser cover plate there should be a screw that is close to the focus know. That should just be a cover screw. That screw comes out and will expose the knob inside the cover that is attached to the pinion gear. As you rotate the know you will see an allen head screw. Loosen that one, then turn it some more and a second allen head screw will appear. Loosen that one. That should allow you to take the knob off.


If I read that right, it should be that very first silver screw? Or perhaps the one below it out of frame since the one pictured here looks rounded off but could be bad angles and lighting

#8 wxcloud

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Posted 03 December 2020 - 02:55 PM

Well, I've made no progress on this. Still trying to figure out the logistics of actually mounting the focuser and solve some back heavy balance issues at the same time.

I also discovered in addition to the grub screws on the bottom of the focus cover, there are some on the backside also.

Might just scrap the idea of autofocus on this set up.

 

Edit:

 

So ehem.... I got the knob off after trying all the silver grub screws on that side. Was the black ones in the knob itself... Yeah... crazy.gif blush.gif

 

 


Edited by wxcloud, 03 December 2020 - 04:20 PM.


#9 HIbill

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Posted 22 February 2021 - 03:25 PM

no one figured this out? Exactly which screws come out and how do you attach an EAF focuser to the a AT (at92 in my case). do 2 screws hold the eaf bracket to scope? I got the knob off.


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