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Comet Catcher Secondary Mirror removal

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#1 Eddgie

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Posted 24 May 2018 - 11:26 AM

I just bought another Comet Catcher (my second one.. Sold my first and regretted it after a year).

 

I am going to take the scope on a driving trip and when I get back, my intention is to pull the mirrors and send them in for modern, protected coatings.

 

The question is, how is the secondary mirror mounted?  I can see that it is in a can, and I can see that there is a big Phillips head type screw that goes into the front and my guess into the can, and there are three small collimtion screws that one would guess acts on the can to tilt it.

 

How though is the secondary mirror held in this can? Anyone know and any thoughts on whether it can be removed?

 

A hand drawing would be nice if you have experience tearing one of these down.

Thanks!



#2 Eddgie

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Posted 24 May 2018 - 11:40 AM

Never mind.. I have my answer.  The flat is held into the can by a small metal tab that simply screws to the side.

 

Documented here in case anyone else ever has the question.

 

CC Secondary mirror.jpg

 

(Of course I had to pull the secondary stalk out to see this, but this proved to be pretty easy.. Two screw hold it to the sled.)


Edited by Eddgie, 24 May 2018 - 11:42 AM.

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#3 *skyguy*

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Posted 24 May 2018 - 11:57 AM

Good information, Eddgie. I've also been thinking about having the mirrors re-coated in my Comet Catcher, but I'll wait until winter, when I don't get a clear sky night for at least 3 months straight (no exaggeration). I'd be interested to hear how well ... or not so well ...your new mirror coating are working out. Please keep us posted. Thanks.


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#4 Eddgie

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Posted 24 May 2018 - 03:50 PM

Will do.

 

I am off on a driving trip in a couple of weeks and taking the Comet Catcher with me, so I won't get to this before I go.

 

Plan is to send it away for recoating as soon as I return.

 

I inspected the mirror today when I opened the tube to get at a dent (successfully removed) and while there, since had the secondary out, I ran a tight beam of light across the mirror face.  I could see that the reflectance seemed uneven with some spots looking like they have a super pale blue tint.   

 

I don't know how to tell if a coating is bad, but this one did not look quite right.  Probably more than 25 years old I guess, and I doubt that these were SiO2 overcoated, so a new coating can't hurt.  

 

These are great scopes and worth the money to have this done.




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