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Posts Made By: Chuck Edmonds

November 2, 2003 11:53 PM Forum: Equipment Talk

Schaefer Mounts...

Posted By Chuck Edmonds
Schaefer mounts were made by Bill Schaefer from the mid 1940s until the mid 1990s. Shortly before his death Bill sold the business to AstroTrak (sp?). I don't think they are in current production. There are some people in So. Cal. building similar mounts on a custom basis. Schaefer mounts are a close coupled GEM using Byers gears. They are very sturdy and can support quite heavy loads. A 12" mount of this general design can support OTAs of close to 200lb.

May 19, 2004 08:44 PM Forum: Equipment Talk

Who put the EQ in the EQ mount?

Posted By Chuck Edmonds
I believe that Fraunhaufer (sp?) invented the German equatorial mount.

August 24, 2004 01:01 AM Forum: Telescope Making

Any ceramics experts here?

Posted By Chuck Edmonds
Quite few years ago S&T ran a brief article about a guy experimenting with ceramics for mirror blanks. I don't recall any follow up as to success or failure. If you have access to past editions you might try looking up the article.

December 3, 2004 04:08 AM Forum: Telescope Making

Hurst motor repair or replacement

Posted By Chuck Edmonds
Have you tried replacing the capacitor? A bad capacitor can cause the kind of problem you are seeing.

September 23, 2005 01:18 AM Forum: Equipment Talk

Any experiences with Enterprise Optics

Posted By Chuck Edmonds
I have a 16" f/5.5 I bought from him back in the early 1980's. I think it's a first rate mirror. I've had many folks say it has produced some of the best views they've ever had.

Chuck

September 10, 2006 02:53 AM Forum: Telescope Making

Clutch Material for a GEM Polar Axis Drive

Posted By Chuck Edmonds
In his older mounts Schaefer used sheet brass for a clutch. There were occasional problems because cutting the brass sometimes warped it. He later switched to linen phenolic for the clutch. He also switched from teflon to HDP for the thrust bearing because of teflon's tendency to cold flow under pressure causing problems with the worm alignment. I've had good luck with canvas phenolic which is much cheaper than linen phenolic. Whichever you use be sure to scuff it up with 100 grit sandpaper on both sides.

April 23, 2008 04:35 AM Forum: Telescope Making

Speaking of Teflon

Posted By Chuck Edmonds
I tried using UHMW for the thrust bearings in a Schaefer style GEM. The UHMW had too way too much stiction, although lubricating it with Superlube helped a lot. I ended up using HDP instead. It works much better for the application. The reason I didn't use Teflon was that Teflon cold-flows under pressure which eventually messes with the worm gear alignment.

December 18, 2009 02:54 AM Forum: CCD Imaging and Processing/Deep Sky

How many are using OAG vs. Guide Scope?

Posted By Chuck Edmonds
I have been using the onboard guiding on my ST10 at 2500mm and 2900mm. I have rarely had problems finding guide stars.
I preview the imaging field and the guider field with the CCD overlay in Megastar.

Chuck

January 30, 2010 12:31 AM Forum: Digital SLR AstroPhotography

stacking software compatible with Windows 7

Posted By Chuck Edmonds
Have you tried "Run as Administrator". I have found it solves all kinds of issues.
Also, I sometimes have have to do it installs.

Chuck

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