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Optimizing an SCT, simple steps

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#51 Mike B

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Posted 12 July 2005 - 10:22 AM

careful, Scott... that might make you a... dare i say it? A SSCTF! :tounge:

#52 Scott Beith

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Posted 12 July 2005 - 11:37 AM

For a 14" LX200GPS-SMT with UHTC I will take that chance. :lol:

#53 Starman1


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Posted 12 July 2005 - 01:06 PM

I've seen a C-11 with 12 large square holes cut in the tube, making the scope very open to the passage of air in/around the mirror. The owner claimed thermal issues ceased after 20 minutes. He also pointed out he just blows the accumulated dust off the mirror. "Really no different than a truss dob".

I'm really considering doing that. My fear is, wouldn't I risk bending the tube while cutting/drilling the hole?

His holes were squares with rounded corners, and I think I recall he said they were laser-cut. If I recall correctly, he had 9 holes in the tube, and each one was about the size of the palm of my hand!
If you use a tiny pilot hole and a high-speed drill, the tube probably won't be bent. You can also leave the corrector and mirror cells on the tube when it's cut, and that will stiffen the tube substantially.
But, a better question is: "Does cutting holes in the tube solve any problems in thermal management not already solved by a Lymax SCT Cooler?"

#54 Mike B

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Posted 12 July 2005 - 01:56 PM

I think i may have seen a book on that procedure:
"Hole in My Scope"
by I.C. Moore

#55 Victor Kennedy

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Posted 12 July 2005 - 05:34 PM

Where I live the temperature doesn't swing wildly in the evenings so I don't find that much of a problem. It does get humid, though, so I've found a home-made dewshield useful (on occasion I've forgotten it, but pointing the corrector down for a few minutes helps get rid of the dew).

The accessory I have found most valuable was a 2" diagonal and a couple of widefield eyepieces. They really made the biggest improvement, IMO.

I added a Feathertouch 2-speed focusser, which is nice.

For me, getting a goto mount was another big improvement, but that may be off the topic here.

I'm still searching for the ideal finder, though.

#56 NorthCoast



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Posted 13 July 2005 - 08:11 AM

In regard to collimation were "bob's knobs" mentioned?

I read above from Don " Right Angle Correct Image focuser". Was the intent to be "RACI finder"? I would second that suggestion.

How about stainless steel screw/bolt replacements? (Not visual improvement and may be off topic, but it is simple?)

Does a mounted 80mm wide view refractor count as a modification? ;)


#57 Mike B

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Posted 13 July 2005 - 06:34 PM

Hi Victor-

Yes, the SCT design is pretty claustrophobic for FOV, so the upgrade to a quality 2" diagonal and visual-back is nearly a necessity! :ubetcha:

Oddly enough, i'm presently in the process of making a home-brew dewshield as we speak. I need it for dew and off-axis light/glare... easier than flocking the interior of the tube ;)


Good call on the "Bob's Knobs"... got 'em, just ain't installed 'em. Maybe for Mars i'll bite the bullet & do it.

Thanks for the suggestions... keep 'em rollin'! Every now-and-then it's good to distill all the good stuff that's been buzzing around into one thread for others to reference- i know i've benefitted from such- hope this thread can do same for others who are trying to get the most out of their SCT.
:cool: mike b

#58 southmike



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Posted 13 July 2005 - 10:02 PM

I guess the thing to add would be quality items are worth it most of the time...one example of this is a Barlow ..
while it is not a sct specific item , it is an item that can do more damage then good if it s a really poor performer, it will cripple your sct.

more additions....
now some of these depend on the run date of the scope but most of the list involves peterson. and all are for meades.

some other things to look into adding.
peterson ez clutch kit, focuser bearings, ez grip handles,
bucks gears , and replacement dec knobs. most of those are gps units only.... the new runs don't need bucks gears as they are metal. also 10" and bigger can use the eyeopener II's
and 10" and bigger classics might look into the mirror locks.

#59 Joel



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Posted 14 July 2005 - 05:33 AM

The used Meade I just bought has all the Peterson's mods. I also got a couple years of Sky Assurance warranty transferred to me. But here's the catch, if I send it back to Meade for service later, they can refuse to honor the warranty due to the aftermarket mods. I would have to put the old plastic gears back in I guess. Bummer.

#60 Guest_**DONOTDELETE**_*

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Posted 14 July 2005 - 12:52 PM

Depending on your mount, you may want a Polar Finder Scope. This makes seeing and finding the north star and true north a lot easier than just looking through the hole in your mount.

A compass is also a good tool to get your mount set in as close of position to true north as you can before polar aligning.

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