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Fine Focus for a Mewlon 210

catadioptric
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#1 APO1

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Posted 13 September 2019 - 08:23 PM

Just received a MoonLite focuser for my Mewlon 210, what a huge difference it made in being able to obtain fine focus, extraordinary results. If you have a 210, and are sitting on the fence about adding fine focus, make the jump. It's worth it!

 

Dan



#2 jefffed

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Posted 13 September 2019 - 09:15 PM

Any Pics? I was going to go low tech with a Scope Stuff aux. knob that fits over the Mewlon's



#3 petert913

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Posted 13 September 2019 - 10:40 PM

It always surprises me how Takahashi just neglects the need (and marketplace) for quality focusers on their scopes.  It's not like  you

don't pay enough for them :)


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#4 fred1871

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Posted 13 September 2019 - 10:53 PM

Yep, basic focuser is not ideal - I've added a Moonlite to my Mewlon 210, in preference to the Tak add-on fine focus item. The Moonlite works very well and is a definite improvement on the basic system. Eliminates mirror-shift issues in focusing as well as finer focus ability.



#5 Kunama

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Posted 13 September 2019 - 11:02 PM

It always surprises me how Takahashi just neglects the need (and marketplace) for quality focusers on their scopes.  It's not like  you

don't pay enough for them smile.gif

There is a reason for them not to have a second focuser on the Mewlon 210 as standard equipment, the back focus for best correction is 44mm from the rear of the scope's standard visual back, after that you have a further 118mm of available back focus (by moving the primary closer to the secondary)  but the further you go the more you move from the optimal focus position ..... That 44mm is also about the light path of the smaller Tak prism...... 


Edited by Kunama, 14 September 2019 - 04:56 AM.


#6 fred1871

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Posted 15 September 2019 - 12:57 AM

There is a reason for them not to have a second focuser on the Mewlon 210 as standard equipment, the back focus for best correction is 44mm from the rear of the scope's standard visual back, after that you have a further 118mm of available back focus (by moving the primary closer to the secondary)  but the further you go the more you move from the optimal focus position ..... That 44mm is also about the light path of the smaller Tak prism...... 

Not sure I've seen a difference, between when I was using the Tak r&p and now with the Moonlite. That's with the small Tak prism diagonal. Equal double stars at 0.35" or thereabouts still show slight elongation at 480x, confirmed at 690x (Nagler 5mm and 3.5mm).

 

I see you're using a Baader Maxbright diagonal on your Mewlon 210. Does that fit for the preferred back focus for best correction? Interested, not attacking. smile.gif



#7 Kunama

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Posted 15 September 2019 - 02:18 AM

I'm using my Mewlon with binoviewers so I am at the maximum backfocus setting.
I now have the Baader 4in1 clamp on the Mewlon to shorten the light path as much as possible.

#8 APO1

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Posted 26 September 2019 - 03:50 PM

Okie doke. Here's a pic of the MoonLite attached to the Mewlon.

 

Dan

Attached Thumbnails

  • 20190915_191456 (002).jpg


#9 payner

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Posted 26 September 2019 - 04:52 PM

Very nice indeed, Dan. And the 41-mm Panoptic is an awesome eyepiece.



#10 amys

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Posted 28 September 2019 - 09:49 PM

I use a FeatherTouch, adapted from the Intes Micro Mak I sold to help pay for the Mewlon.  Much better than relying on the Tak focusing knob.  Way too much focus shift, like with my former NexStar.



#11 amys

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Posted 30 September 2019 - 10:19 AM

Should have said mirror shift.  That, and the fact that there is no way to mount a straight through finder or laser pointer are the only things I dislike about this amazing scope.



#12 dr.who

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Posted 01 October 2019 - 11:49 AM

It comes with a straight through finderscope that does very well. If you mean a RACI Telescope Service in Germany sells a adapter to make it a RACI. For laser I just shine it through the finder or scope EP. that gets me in the general area and I can fine tune with the included finder and then EP from there. Alternatively you can buy Parallax or Prima Lucie Labs rings for it, put a rail on top of the rings and mount whatever you want.



#13 dr.who

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Posted 01 October 2019 - 11:52 AM

Mirror shift is a potential problem with the 210. You can either adjust it per the directions posted in another thread here, use a after market focuser like I and others do, or just accept it.



#14 macdonjh

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Posted 01 October 2019 - 12:00 PM

I thought Takahashi scopes came pre-focused from the factory?



#15 dr.who

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Posted 01 October 2019 - 01:23 PM

Not sure what you mean by pre-focused. They come collimated from the factory but focus is dependent on EP's, diagonals, BV or no BV, and other factors so they can't be "pre-focused" because of all the variables. 




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