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Posts Made By: Guy Jordan

September 17, 2006 05:39 AM Forum: Equipment Talk

Telescope as telephoto

Posted By Guy Jordan

I ran into this link on Usenet ( about an f/4 1700mm lens. The claim is that this custom Zeiss optic cost ~$200,000!

The question is, how well would a telescope be able to compete against a monster like that... or what would it take to compete? My first thought is a 17" f/4 dob with a Paracorr. What says you?


May 3, 2007 05:04 PM Forum: AstroMart FAQ

Deepest sympathy

Posted By Guy Jordan


Words can seem too hollow for the need and fail to convey our hearts well enough but we try. Thank you for sharing this news with us; your respect and consideration in this difficult time is a real measure of a man. We offer our deepest sympathy for the loss of your father.

Guy Jordan and family

October 17, 2007 08:30 PM Forum: Celestron

Whatever happened to...

Posted By Guy Jordan

Whatever happened to Celestron's 20" Dall-Kirkham telescope? It's been like three years since it was announced and I lost track of it.


May 3, 2008 03:14 PM Forum: Telescope Making

Proposed Fresnel imager

Posted By Guy Jordan

I ran across this article:

...which describes a technique for creating a very large high resolution Fresnel telescope.

Anyone aware of this being done in an amature instrument?


June 1, 2009 08:57 PM Forum: Celestron

ATWB & Celestron

Posted By Guy Jordan

So just a "late to the party" question, why no Celestron product at ATWB?

April 11, 2004 09:00 AM Forum: Eyepieces

Will the real 18mm please stand up?

Posted By Guy Jordan

Nice to have those options. So, how do the views compare?


April 25, 2004 02:23 PM Forum: Bad to the Bone Autos

Ford GT

Posted By Guy Jordan

Not much room for a telescope in there.

May 4, 2004 04:34 PM Forum: Telescope Making

Cooling idea - great or nuts?

Posted By Guy Jordan

Theory vs. practice:

Would the additional active cooling from this type of radiator cause distortion in the mirror surface?

Is it possible that cooling a mirror too fast could damage it if it was too thin for its mass?

Flip side, if the entire mirror were aluminized rather than just the optical face, would the extra area be an effective radiator?

Failure analysis is one step away from paranoia... but which way?


May 7, 2004 06:29 PM Forum: Telescope Making

Moonlite vs JMI

Posted By Guy Jordan

I have nothing to offer except a further question :0

Have any of you looked at the van Slyke Engineering Microglide and Masterglide focuser? The result looks impresive on the web site but are they really? How well do they compare to the Moonlight, Feathertouch and Clement?

Also, what makes these premium machines worth their price and what makes one better than the other?


May 12, 2004 10:38 AM Forum: Telescope Making

project TMB175 f/8

Posted By Guy Jordan

Their may be a good reason the machinist is reluctant to remove so much material. How much material are they comfortable removing?