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Vic,Jason and Nils I have another problem.

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#26 alonzo

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Posted 30 November 2013 - 12:58 PM

...Today I am going to move my primary the amount indicated by the formulae thats in by Peter Francis book "NEWTONIA NOTES".
It says my focuser should be 38.45 inches from the front of my primary. I think I will round it off to 38.375" as I have nothing to measue in thousnds. All this will do is raise my focal plane just a hair more. I don't think it will cause any problems. I sure hope I am not moving my mirror clips out of view as that would be bad.

Alonzo

#27 backwoody

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Posted 30 November 2013 - 09:46 PM

Alonzo, we will await your report on results! Good luck with the project,

#28 alonzo

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Posted 30 November 2013 - 11:13 PM

...Thanks Woody I'll keep everyone posted.

Alonzo

#29 alonzo

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Posted 01 December 2013 - 06:47 PM

...Didn't get to move mirror today but played with a little math. The "NEWT" program and formulae in the Peter Francis book come out to be exactly the same. Front of primary mirror to focuser hole should be 38.8125". Since they show this with no variation I suppose this is what it is for my system. Since with my crude garage tools I think I will round it off to 38.675". This will raise my focal plane by
.1375" which isn't very much to be concerned with. Vic I know I am not following your suggestion on bringing the ota outside and leaning it up on something. The telescope unfortunatly is too heavy for a move like that. Its a sonotube painted with several coats of fibremesh and resin incased in a coopered wooden tube. I have many light baffles I cut with a router that also adds to the weight. I made a ringed slipon housing to accomadate the tube with a harness.
When I get the mirror moved I will mount it on my fork but not before I see where to mount some counter weights. I don't know if you remember how heavy the Coulter mirrors were back in the day but the were big hernia things. I will be using a comealong to lift it a little to find the CG. I will keep everyone posted as I proceed.

Thanks
Alonzo

#30 Vic Menard

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Posted 01 December 2013 - 07:51 PM

:fingerscrossed: ;)

#31 backwoody

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Posted 01 December 2013 - 07:55 PM

Alonzo, hmmm....sounds like you need about 1/8 inch upward movement of your primary. Take a close look at those collimating screws and springs to see if there is 1/8 inch available before doing anything more. Hope the fix is easy.

#32 alonzo

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Posted 01 December 2013 - 11:30 PM

...Woody how are you coming up with this. I don't think 1/8th of an inch will get me here.

Alonzo

#33 backwoody

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Posted 02 December 2013 - 05:33 PM

Alonzo, I might have misunderstood a previous post; I think you calculated raising the focal plane by .1375". That would be just a bit over 1/8 " (.125").

Sorry for any confusion!

#34 alonzo

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Posted 04 December 2013 - 07:27 PM

...Having finding the primary was far more difficult to move than I thought I elected to move the secondary and focuser. Trying to line up holes of the primary mirror cell with new holes in the tube just could not be done especially with the weight of the mirror. I did the best I could in transfering my measurements and I think I did O.K.,only time will tell.
Tommorrow I will try starting the process centering my secondary under the focuser. I did a preliminary check and it seems I am going to have a little lateral problem. It appears I have more space on the bottom between the secondary and focuser tube than I do at the top. Maybe shimming my focuser would help I will just to look at it closer tommorrow.

Alonzo






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