From: "Milton Aupperle" <milton@outcastsoft.com>

Date: August 12, 2008 10:51:27 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Autoguiding...

--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:

Hi Milton, I`ve just written to Frank from the Autoguiding Yahoo

group about guiding using the set-up I had in mind with the Orion

Short Tube 80 Guidescope & Astro IIDC. Here is what he said in part;

"As for guiding the big C10, I expect the mirror will cause flexure 

problems, so be prepared to see oblong stars at long exposure.  But if 

you keep exposures to 1-4 minutes, and depending on where in the sky 

you are imaging, it may work ok."

I think Frank (FreeStar8) is under the impression your C10 is a CAT

scope, which means the mirror slides up and down on the greased baffle

/ shaft through he center of the mirror. The only reason you would

have mirror movement in a Newtonian is if the mirror isn't securely

held in the mirror cell.

Also with respect to using the Unibrain Fire-i webcam as a guide

camera; "I guess that camera uses a Sony CCD.  It looks like it is

uncompressed 

color camera?  The color isn't ideal for guiding, but non-compressed 

will help." To your knowledge is the Unibrain a non-compressed

camera? He says also that PhD has a Mac version. How does it stack up

against Astro IIDC for guiding in your opinion? Mark.

The Unibrain's are uncompressed, however the longest exposure it can

do is 1 second. With an 80 mm guide scope scope the best your going to

reach is maybe mag 6 or 7 guide stars (this has been discussed at

length about in the past in the archives of this group too).

And I've never tested PhD because it won't display video with any of

the dozen or so FireWire Mono / Color cameras I have here or on any

Mac with 10.4.x or higher. If I can't use the camera in doors from my

desk, there is no point trying it on a telescope, so that's as far as

I got with it.

Lastly, until you solve your pointing / alignment issues with the 10"

Newtonian and it's mount, your wasting your time trying to guide with

any product. Without accurate polar alignment, you will be come very

frustrated with any product trying to guide with it. It simply isn't

going to work reliably.

HTH..

Milton Aupperle