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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 :)



#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.


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