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ETX collimation

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#1 Doneb

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Posted 19 September 2013 - 08:15 PM

Greetings! The ETX's are on my list as a second scope but I was wondering if anyone has ever had collimation issues with the Mak-Cass models? I understand that any problem with collimation would have to be handled by someone with expertise. Thanks in advance for your comments.

#2 Christopher Erickson

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Posted 20 September 2013 - 02:25 PM

Mak's are effectively pre-collimated at the factory and are not adjustable by the user.

What does a star test look like?

#3 Don Taylor

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Posted 20 September 2013 - 06:13 PM

Mak's are effectively pre-collimated at the factory and are not adjustable by the user.

What does a star test look like?


Not true. The etx90 primary can be collimated and mine needed it. The secondary and minisicus are not collimateable.

The etx mak scopes use 3 pairs of push-pull screws on the backplane and are accessible after removing the plastic visual back. Collimation is tedious because you have to keep removing and reinstalling the visual back for each iteration.

#4 Doneb

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Posted 20 September 2013 - 09:10 PM

No star tests as I have not decided on this scope yet. I was just wondering how common (or rare) it is for these Maks to get out of collimation and how big a chore the collimation would be. Thanks for the replies guys!

#5 Don Taylor

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Posted 20 September 2013 - 09:19 PM

I should add that (with mine anyway) the collimation has been very stable - both before and after re-collimation. Previously gave a slightly off center star test. Great now.

#6 Doneb

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Posted 20 September 2013 - 11:19 PM

Thanks, Don I suspect the vast majority are stable. I know there are a lot of happy ETX-er's out there and if it were a common occurrence that would not be the case. Also, I see a lot of used ETX's on eBay and wonder why.

#7 Christopher Erickson

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Posted 21 September 2013 - 02:16 AM

Mak's are effectively pre-collimated at the factory and are not adjustable by the user.

What does a star test look like?


Not true. The etx90 primary can be collimated and mine needed it. The secondary and minisicus are not collimateable.

The etx mak scopes use 3 pairs of push-pull screws on the backplane and are accessible after removing the plastic visual back. Collimation is tedious because you have to keep removing and reinstalling the visual back for each iteration.


Note that I said "effectively".

Meade does not document or encourage users to open up their Mak scopes and play with the insides.

#8 mayidunk

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Posted 25 September 2013 - 08:06 AM

Mak's are effectively pre-collimated at the factory and are not adjustable by the user.

What does a star test look like?


Not true. The etx90 primary can be collimated and mine needed it. The secondary and minisicus are not collimateable.

The etx mak scopes use 3 pairs of push-pull screws on the backplane and are accessible after removing the plastic visual back. Collimation is tedious because you have to keep removing and reinstalling the visual back for each iteration.

Actually, Dr. Clay Sherrod discourages anyone from attempting to collimate their ETX Maks! Read this!

Unless you are absolutely, positively, beyond any shadow of a doubt, sure that your ETX is out of collimation (unfortunately, you cannot reliably test this with an out-of-focus star image on this type of Mak), then put down the Allen wrench, step away from the scope, leave it alone, and stop worrying about it!

Quit obsessing, and just enjoy your scope!

:grin:

#9 Doneb

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Posted 25 September 2013 - 09:33 PM

Thanks for the article, Bob. I don't have one of these scopes yet (indecision may or may not be my problem) -- just wanted to know if Mak collimations was an issue to consider if or when I decide to get one.

Clear skies!

#10 Darren Drake

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Posted 28 October 2013 - 11:59 AM

My 125 was slightly outa coll with the mirror flip focus but I easily fix it by derotating the correcor assembly about 3/4 of a turn and its perfect. So I am always making sure that the "1900" is at about the 1 o'clock position and I will know collimation is good.






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