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Posts Made By: Walter Hamler

April 12, 2002 10:20 AM Forum: Telescope Making

Apology to Mark Harry

Posted By Walter Hamler

I called you "Harry" in an earlier post. Oops! Sorry Mark

April 12, 2002 02:13 PM Forum: Telescope Making

What do I have here?

Posted By Walter Hamler

Well, I just finished making a mask to check readings on my 10" f/6, and I would like some of you out there to tell me how close I am. Actually, I think I'm darn close, but some of you may have a number crunching program that will tell me. I'm an old geezer and math was a long time ago!
10" mirror, 121.2" RC. I checked at the 32%, 70%, and 95% zones. Readings (avg of 4) are. 0, .025, .101, and .180. My math says I'm only a few thousands away from perfect, if I understand the process.
Anxiously awaiting your responses.
Walt

April 15, 2002 06:15 PM Forum: Telescope Making

Lensless Schmidt cameras

Posted By Walter Hamler

MANY years ago I bought an 8" f/2 spherical mirror and film holder from Coulter Optical in CA. The idea was to make a lensless Schmidt camera by placing a field stop at the RC of about 5" in diameter. That, in conjunction with a curved film holder supported by a spider vane, was supposed to give relatively good astro images on 35mm film or 2" circle cut film. Well, I never actually put it together, and sold the set some time ago. Now, a friend has a 10" f/2.95 spherical primary that he wants to use for the same purpose. He is proposing a 7" aperature but projecting the image out to a camera body via a 3.1" diagonal. I'm leary??? Any knowledgable inputs/experiences out there?
Walt

April 27, 2002 04:31 PM Forum: Lost Contacts and Personal Messages

Tim Hogle

Posted By Walter Hamler

Anybody in So. CA know of/wherabouts of Tim Hogle. I last saw him in 1978/79 at the ASTROphoto Conference. He was working JPL at the time.
Walt Hamler

May 20, 2002 06:12 PM Forum: Deep Sky Observing

Gamma Virginis Revisited

Posted By Walter Hamler

Tonight was the first clear night since getting my recently completed 10" f/6 back from the coaters. A cold front had just moved through so typically the seeing is horrible for the first day but I had to try. Looked at Jupiter, but being low was greeted by typical mushy appearance due to lower altitude. Looking directly over the roof of my house didn't help either! However, the occasional moments showed the moons as tiny littlt discs at 120x, so I was happy. As it got darker I switched to Castor, but that was too easy. So I turned around to Virgo, found Gamma, and even at 120X, I could tell it was double. Put in the 2.5X and voila!, there they were, two perfect little discs floating in mostly mush. Well, you know what I mean, not perfect discs, but when it momentarily cleared, they looked great. I'm HAPPY!
Walt

May 31, 2002 06:25 PM Forum: Telescope Making

Re: Enlarger lens

Posted By Walter Hamler

In the case of an enlarger lens, the listed f is the focal length, the f/number is the speed, ie f/4.5, so the approximate aperature would be 164/4.5 = 36.4mm. It really wouldn't make a very good telescope, but a useful small finder maybe.

June 2, 2002 02:06 PM Forum: Equipment Talk

Feathertouch Focusers

Posted By Walter Hamler

Anyone out there who owns a Feathertouch focuser, can you tell me how the focuser unit attaches to the base? I am considering buying just the basic body and adapting it to the base of a current 2" focuser.

Walt

June 5, 2002 08:41 AM Forum: Telescope Making

Flocking Material

Posted By Walter Hamler

I recently purchased a sufficient quantity of the black flocking material from Protostar to put in the tube of my 10" f/6 dob. It is an outstanding product and works as advertised in every way, albeit a little difficult to install in my case. They actually sent me more than I ordered so I had enough to do most of the tube for my 8" f/6 also. Anyway..... Yesterday I was browsing the McMaster-Carr website Http://www.mcmaster.com and found a listing for velvet, self adhesive back, 45" wide. I ordered 3' just to see. It arrived this AM!!!! and it is the same stuff as what Protostar sells. Price is 4.26/ft and works out to about 65% of the cost through Protostar. It also is available in a plain, non-stick backing for even cheaper price.
Walt

June 11, 2002 01:20 PM Forum: Equipment Talk

Drive Correctors

Posted By Walter Hamler

Are there any new drive correctors out there for 115vac synchronous motors? I have seen a couple used ones for sale on Astromart that were the old Bradford-West kits, and someone told me that JMI used to make one but no longer.
Otherwise I'm going to have to convert to stepper and don't really want to.

Walt

June 21, 2002 04:56 PM Forum: Telescope Making

Moonlite Focuser revisited

Posted By Walter Hamler

Back in April there were some posts on this brand focuser. After some comparison shopping and looking, I bought one, but got a Black version, as I guess I'm old fashioned!! Anyway, its truly is a very nice unit, and Ron Newman was very helpful and a pleasure to deal with. NOW, please let the clouds depart!!!

Walt