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Looking for information about Dynamax 6 SC

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#1 Thomas Karpf

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Posted 18 November 2005 - 09:05 AM

I recently acquired a Dynamax 6 Schmidt-Cassegrain, including yellowish tripod, blue wedge, a variety of electronics, and a couple of eyepieces (a 12.7mm and a 16.3mm Erfle). I picked it up at the ASGH auction on Wednesday for a whopping $80, including all the parts. Seemed like a decent deal. I hope to get a chance to look through it this weekend.

What I didn't receive was a manual.

Would anyone have any idea where I might be able to find one?

Thanks.

Clear Skies!

#2 Rat8bug

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Posted 18 November 2005 - 10:46 AM

Well, the Dynamax was the "Bottom Feeder" of SCT telescopes. But what the heck, for $80 you won't lose anything if it lives up to its reputation. Try this link:
http://members.aol.c...ISE/index4.html

Ciao...Barry

#3 Gary

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Posted 18 November 2005 - 11:00 AM

Google Telescope, will get you lots of infomation on it.

Gary

#4 Thomas Karpf

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Posted 18 November 2005 - 11:58 AM

That site is defunct. The new link is:

http://skywatch.brai...oland/index.htm

#5 Pierre L.

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Posted 22 November 2005 - 09:06 PM

Hi! Tom
I have the Dynamax 6 & 8 owner manual in pdf format, if you want a copy send me a PM with your e-mail adress. :smirk:

#6 dougspeterson

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Posted 24 November 2005 - 12:11 PM

A lot of people badmouth these scopes who have never actually looked through one. I actually own a six and the good news it is optically excellent! I have no explanation as to whether it is the luck of the draw, or the sixes received more attention. In any case the bad news is mine vignettes to about 5" with the diagonal in place, you get the full 6" straight thru. The mount is almost unbelievably smooth and silky, and solid. 80 bucks has to be one of those steals one can only dream of.

#7 Thomas Karpf

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Posted 29 November 2005 - 11:55 AM

The mount seems okay, but the optics are kind of iffy.

Views through a 32mm eyepiece (about 48x) were good. Views through a 20mm Televue Plossl (about 76x) were okay, but a little fuzzy. Views through a 6mm eyepiece (about 250x) simply wouldn't come to anything that resembled focus.

My target was a radio tower about 2 miles away, so the atmosphere wasn't much of a consideration.

The scope has four optical surfaces. From what I've read elsewhere, the corrector was built by taking a piece of plate flat glass, pulling it against a mold with a vacuum and grinding/polishing the other side. Assuming the engineers knew what they were doing (and I have no reason to assume otherwise), I'd expect the following to be true:

1) The primary mirror is fine. It's a spherical surface, and
I'd be amazed to find a problem there.
2) The secondary mirrir is fine. It's probably spherical. Same comments as the primary.
3) The oddly shaped side of the corrector is fine. If the mold was built correctly, then all they had to do was grind and polish the exposed surface. If there were small imperfections in side of the corrector that was held against the mold, those imperfections may have had no impact in how the glass was held against the mold.

4) The surface that was vacuumed against the mold could be the problem. Potentially, all I need to do is grind this flat. It might be worth it to test the 'flat' side to see how flat that corrector is.
5) Variations in the glass of the corrector could be the
problem. My only option here would be to make a new corrector.

Let's assume that #4 is correct.

How do I polish the 'flat' side so it really is flat? It certainly wouldn't make sense to try and BUY a corrector somewhere when I only spent $80 on the entire scope + tripod.

#8 dougspeterson

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Posted 30 November 2005 - 04:01 PM

I'd try a glint a few hundred yards away in sunlight or an overhead star test at night, to minimize seeing which can easily destroy a 6" image at 250x.

On a schmidt corrector, the "correction" is something like 70-80 waves of spherical abberation on the aspheric side selected to cancel out the contribution from the spherical mirrors. So the tuning of the pair is more likely to be off than the unflatness of the plano side.


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