spiderless at Yahoo! Groups

Dick's Chief...!

mdhopt53 — Sun, 08 Nov 2009 03:14:18 GMT

Looks really nice! It'd be great if we could hear about a comparison between the formentioned Newt form, and the Chief- could you persuade him? Mark

Re: Coma Free Chief

mdhopt53 — Tue, 03 Nov 2009 14:04:44 GMT

Please don't get me wrong, I'm not saying they can't be done easily, just that it took me a week to figure out the variables to do a 6" F/25 concave mirror!

Re: Coma Free Chief

mdhopt53 — Tue, 03 Nov 2009 12:58:05 GMT

Never said that, I never used the planetary rig. I made flats in batches of 50-100 at a time, with generally 6 spindles going. I averaged one in 15 minutes to

Re: Coma Free Chief

Ed — Mon, 02 Nov 2009 15:30:52 GMT

Maybe your mean doing flats on a large planetary polishing machine then yes you're right, a flat is fairly straight forward. Doing a flat or one of these long

North East Astronomy Forum 2010

"Mr. Wizard!" — Mon, 02 Nov 2009 11:30:56 GMT

The dates for NEAF 2010 have been set for Apr 17th-18th. Typically there is a seperate imaging forum the day prior to the Saturday and Sunday exhibits. Save

Re: 300 INCH F 75 HERSHELIAN

"Mr. Wizard!" — Mon, 02 Nov 2009 11:20:22 GMT

Caught!! I was so busy trying to be cute I wrote Hershelian when I was thinking of the Shupman. How could anyone confuse the two! Art ... It's not as low a

Re: Coma Free Chief

mdhopt53 — Sun, 01 Nov 2009 11:54:10 GMT

They're a whole different ballgame when it comes to making the thing. I found that the pitch layer on these long radii pieces have to be essentially the same

Re: eyepiece info

Dennis — Sat, 31 Oct 2009 21:30:19 GMT

If'n anybody is interested Surplus Shed has a complete reprint (probably Zerox) all 630 pages for the meager sum of $50.00. Dennis

Re: Coma Free Chief

kevin frederick — Sat, 31 Oct 2009 18:38:03 GMT

wow ED sounds like you are finding out alot of new things . so cool ... From: Ed Subject: [spiderless] Re: Coma Free Chief To:

Re: Coma Free Chief

Ed — Sat, 31 Oct 2009 17:45:28 GMT

One more thing I discovered about this design (sorry for all these short posts). The secondary can be flat or curved over a wide range. However if I make the

Re: eyepiece info

Richard F.L.R. Snashall — Sat, 31 Oct 2009 16:57:45 GMT

... A little C&P helped. It's not the chapter that is missing, just the main page link to it that is bad.

Re: Coma Free Chief

Ed — Sat, 31 Oct 2009 16:23:37 GMT

Playing around with Zemax I found that you can get about the same results without using a mangin using a very long radius hyperbolic secondary. I'll post the

Re: Coma Free Chief

Ed Jones — Sat, 31 Oct 2009 15:22:54 GMT

Mark, Obtaining a smooth surface on these would be no different than doing a flat plus you would have a few fringes of tolerance that you don't normally have

Re: Tube alternatives for larger aperture mirrors

"Mr. Wizard!" — Sat, 31 Oct 2009 15:13:13 GMT

Hi Tony! I just now spotted your request for info. Sorry for the delay. The photos in the picture section were taken of a tube purchased locally at a building

Re: Coma Free Chief

kevin frederick — Sat, 31 Oct 2009 13:11:12 GMT

HI MARK sounds like you are the guy to make me a Chief mangan corrector .kevin . ... From: mdhopt53 Subject: [spiderless] Re: Coma