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Meade 12 LX200 (Not ACF) Backfocus for PF AP?

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#1 Adam E

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Posted 02 February 2013 - 11:36 AM

Hello CAT lovers,

I have a 2006-ish vintage Meade 12 OTA (not an ACF scope) that I regularly enjoy using for planetary fun. I recently picked up a T4i that has found itself on my old Vixen ED80sf for a night of giggles with M41/42, and I'm looking to try it mated up to the big Meade for fun.

I'll be toying around in the wonderful world of coma and F10 as I don't currently have an F6.3 reducer/corrector for the scope.

So, my question is, what would be the ideal backfocus distance between the rear end of the OTA and the camera sensor that I should shoot for?

Any guidance is much appreciated.

#2 rmollise

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Posted 02 February 2013 - 11:51 AM

The distance provided by your prime focus adapter will be fine. But you really, really need to get that focal length down.

#3 Adam E

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Posted 02 February 2013 - 12:16 PM

Hi Uncle Rod. Thanks for the responce, but my problem is that I don't have the standard T-Adapter. I once lived under relatively dark skies and got involved with CCD AP with a number of scopes. I have since moved to light pollution central, have sold the ST8300M I used to use, but I still have all the pieces-parts to mate up the T4i with just about any backfocus distance desired.

So, I just need to know what that distance is, or alternatively, how long the standard Meade adapter is.

And, yeah, I know, dealing with 3000+ mm of focal length is probably going to cross the border into ridiculous, but this is just for fun and curiosity. If all I manage to do this evening is come up with a few train-wreck subs before slewing to Jupiter and pulling out my DBK21, that's all good.

#4 rmollise

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Posted 02 February 2013 - 12:28 PM

About 50mm or so.

#5 Adam E

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Posted 02 February 2013 - 12:46 PM

10-4, thanks! For comedy, I'll update with tonight's antics. :lol: :lol: :lol: :lol: :lol:

#6 Adam E

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Posted 02 February 2013 - 06:20 PM

The plot thickens...

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#7 Adam E

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Posted 03 February 2013 - 11:56 AM

Didn't go too bad, but yes, yes, I do definitely need a reducer / correcotr as this scope is way too much fun to not use effectively.

"The Core" with an non-modded T4i at ISO800, 100 X 30 Sec...

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#8 rmollise

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Posted 03 February 2013 - 11:57 AM

Sweet!

#9 Raginar

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Posted 05 February 2013 - 10:04 AM

I'd be pretty happy with that :) Was that unguided?

#10 Adam E

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Posted 05 February 2013 - 02:52 PM

Thanks Uncle Rod and Raginar! I was guiding with my ED80sf / SSAG piggy-backed.

On a side note, just received shipping notification on my reducer/corrector from Astronomics, and it should be in my hot little hands by this weekend. Might have to roll out the big gun again if the weather cooperates.






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