Refractors at Yahoo! Groups

Re: Long focal length refractor

Doug — Sun, 08 Nov 2009 20:33:44 GMT

An f/9 ED would be a grand scope to consider. Doug ... -- Doug Truckstop Astronomer [Non-text portions of this message have been removed]

Re: Long focal length refractor

Warp — Sun, 08 Nov 2009 20:22:55 GMT

Would you be interested in a pristine classic Meade 102ED APO? f/9 920mm, with rings, MRF finder, dual speed William Optics rotatable 2" Crayford focuser

Selling the BASE PLATE of my TAK TOA-150

Phil Dombrowski — Fri, 06 Nov 2009 21:55:41 GMT

Dear group: I have upgraded the focuser of my TAK. TOA-150 and therefore have put up for sale the light green base plate that screws directly into the 7" white

Re: Long focal length refractor

pacobarrena — Wed, 04 Nov 2009 23:58:30 GMT

Antares has a 105mm in f/9.5 and even longer - up to 1500mm focal length. Good reputation. http://www.antaresoptical.com/vixen-spec-ota.htm

Re: Long focal length refractor

Doug — Tue, 03 Nov 2009 18:08:10 GMT

Most refractors in that f/ratio range are achromats. You would pick up CA on your images, but there is at least one program that can remove the purple halo.

Re: Galileoscope

ancient.sull — Tue, 03 Nov 2009 15:37:28 GMT

I bet that merchant didn't have a very good Astromart rating.

Long focal length refractor

stardaddyed — Tue, 03 Nov 2009 15:04:34 GMT

I am interested in doing a little more imaging using a longer focal length scope, something around f/9 or f/10. I have been looking around and noticed there

Re: Galileoscope

Chris Lord — Tue, 03 Nov 2009 08:05:39 GMT

The Venetian senate employed what we would now term "a fixer", Paolo Sarpi, to strike a deal with a merchant who had a Perspicillum for sale. Sarpi (who had

Re: Galileoscope

ancient.sull — Mon, 02 Nov 2009 23:39:18 GMT

... As I understand it, Gallileo built a _lot_ of scopes. He was constantly refining what he made. Most he gave away to patrons (in return for patronage ).

Re: Galileoscope

Alan French — Wed, 28 Oct 2009 18:46:35 GMT

... Thanks Chris! Definitely a most interesting read. Clear skies, Alan

Re: Galileoscope

Chris Lord — Wed, 28 Oct 2009 08:53:11 GMT

The reason Galileo directed his telescopes to the heavens was to obtain observational evidence to support his belief in the Copernican hypothesis, a belief he

Re: Galileoscope

William Hamblen — Tue, 27 Oct 2009 22:37:40 GMT

... Kepler proposed the astronomical telescope in Dioptrice (1611) and Galileo must have had access to the book. Bud

Re: Galileoscope

Alan French — Tue, 27 Oct 2009 21:47:59 GMT

... I know. I was joking. :-) Clear skies, Alan

Re: Galileoscope

uncarollo2 — Tue, 27 Oct 2009 21:33:57 GMT

... A telescope of that day? I thought Galileo had the only one in his city/country. And he built it himself, for the purpose of exploring the sky. He didn't

Re: Galileoscope

Richard F.L.R. Snashall — Tue, 27 Oct 2009 21:29:47 GMT

... Wouldn't a telescope of that day have been used almost exclusively for terrestrial viewing, and as such have wanted, as you mentioned, only the erect