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Posts Made By: Preston Engebretson

August 14, 2003 09:03 PM Forum: Telescope Making

Source needed for Teflon

Posted By Preston Engebretson


I just ordered some treated Teflon, so that you can contact cement it in place and otherwise one must mechanically fasten it in place. It is the recommended 3/32" thick and a 12" x 12" piece was about $35 from MSC...

Depending on what sizes you need, I may be willing to sell part of mine...not sure if one can do that here, but you could place a wanted add on the Classifieds under telescope making and then I could respond. I'll have it Monday 18 August...


August 15, 2003 11:51 PM Forum: Telescope Making

Cutting PVC 12" tubing >> Salvage effort

Posted By Preston Engebretson

Sam, Rough cut the pieces a bit long with what ever works best...then get a piece of thin flexable plastic or metal that you can get a straight edge on for 36+ inches and wrap that on the ID of the 12" piece until the ends butt together...clamp in place, this is your guide and is now perpendicular to the axis of the tube...then take a router or laminate trimmer with a straight bit with bearing pilot and position the pilot bearing on the thin guide. Work the router around the OD or the 12" tube in small drops and you should get a very nice square finished cut...

Provided that you have a router...

Just a thought,


August 25, 2003 01:08 PM Forum: CCD Imaging and Processing/Solar System

Help with Toucam

Posted By Preston Engebretson

Jim, I'm learning RegiStax2 also and spent most of the day yesterday going between the help on the web page and the program...It's coming SLOWLY!!!!!!!the web page help kind of looks more like version 1 also...

I have found as someone posted 1 vs 300 images, that the program does not do as well selecting clean images as one can do by hand...and that is very time consuming, but the end result is Much better and I beieve that most of the better images are likely hand selected...JMHO


August 28, 2003 12:51 AM Forum: CCD Imaging and Processing/Solar System

Mars and AVI files???

Posted By Preston Engebretson great and easy to use given a little time and watching what is said here regarding the best settings or processing image info...

IMHO Preston

September 13, 2003 11:06 PM Forum: Telescope Making

Hello, BIG, thin Mirror Makers

Posted By Preston Engebretson

Try Mel Bartel's web site...I seem to remember some really
thin large one's that he talks about under thin mirror making.
Just tried to axcess his site but not working now.


November 6, 2003 05:57 PM Forum: Telescope Making

Truss Material. Aluminum bar??

Posted By Preston Engebretson

Steve, I believe most would agree that flat bar stock as you
mention would be totally unacceptable in anything but very short ie...3-6" pieces as far as stiffness is concerned, and this is what one is looking for to keep the scope in collimation...



November 8, 2003 11:23 PM Forum: Telescope Making

Sources For Lightweight Mirrors??

Posted By Preston Engebretson

Bill, you might try Jean-Guy Moreau...he makes a fused mirror
that has a front and back plate of about .500" thickness and is seperated by vertical spacers such that the overall thickness is about 2.5" on a 14" blank that we are working on can either get a blank or finished mirror from him...he is located in Canada and post in Astromart from time to time...I have his email, but Herb's policy is against posting such things I weight on the 14" is something like 14 lbs...


December 16, 2003 02:48 PM Forum: Home Observatories

Geodesic dome - what shape?

Posted By Preston Engebretson

Anthony, Cal's link to Joe Garlitz's site was the beganning of our new dome. Very good instructions. We modified the design slightly by bonding thin 1/4" plywood to the inside and outside faces of the polystyrene, then glassing the seams for reinforcement. Designed a roll back two part shutter built in aluminum. Just now working on the opening mechinism, a cable pull arrangement. The whole project was started Nov 2002, and has taken far longer than I would have guessed. The next problem will be getting it the 25 feet high on the back garage roof, likely or hopefully some sort of crain or lift.

You can contact Joe via email and he is very helpfull. We added the plywood for strength in high wind conditions of the Gulf Coast.

Regards Preston

December 26, 2003 08:57 PM Forum: Telescope Making

Tripod construction question

Posted By Preston Engebretson

Hi Sean, These legs are also black walnut
and dampen the vibrations quite nicely.

Mirror grinder can be seen in back...

Regards Preston

December 27, 2003 10:32 PM Forum: CCD Imaging and Processing/Solar System

Stumped by ToUcam software

Posted By Preston Engebretson

Steve, The link that Derrick gave is the one I used
and I am running 98 on a Toshiba 335cds Satellite at

Works great, but lacks in hard drive space, only 4 mg.

I don't like the Philips software for capturing but
us it with either AstroVidio or K3CCD both of which
look at the Philips drivers.

Hope that helps, Preston