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OMC 140 Mak focuser travel

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#1 mattyfatz

mattyfatz

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Posted 07 April 2021 - 07:11 PM

Struck out in the Cassegrain forum so I figured it’s worth a shot here..

 I purchased is OMC-140 from another CN member. When it arrived the center focusing tube and mechanism was loose inside the tube. The primary was also rolling around in there.

 Except for a very small clam chip on the edge of the primary the damage didn’t seem too bad. I put it back together the way I thought it would go. When I focus the mirror travel is very minute... like only a few cm fore and aft. Is that correct? Seem like a traditional SCT mirror has way more travel. 
I hope someone here can help.

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Edited by mattyfatz, 07 April 2021 - 08:32 PM.


#2 mattyfatz

mattyfatz

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Posted 07 April 2021 - 07:17 PM

02615DF1-1911-4D59-9360-6B47468E87D1.jpeg

Clamchip 

 

4382EEE7-9E2A-4C49-A0C7-F5FB5C95D0AD.jpeg

focuser nubbin. It pushes the mirror against the spring instead of turning on a screw. No mirror shift this way.



#3 clamchip

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Posted 07 April 2021 - 07:50 PM

Wow that's neat.

The micrometer style focuser probably doesn't have much movement.

Is the focus travel being limited by the focuser?

Is this a MCT or a SCT?

 

Robert

 

I did some reading and I think it is operating correctly, travel is limited

by the micrometer focuser.

From my reading I think you will find you have a really excellent telescope.


Edited by clamchip, 07 April 2021 - 08:22 PM.


#4 mattyfatz

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Posted 07 April 2021 - 08:25 PM

It’s an MCT. The design isn’t typical though. It has an ellipsoidal primary which is over 12mm larger in diameter than the Maksutov corrector. So the primary is 152mm while the corrector is 140mm.

Yes, the micrometer only has a little bit of travel.




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