Re: [APML] Guidescope questions

[steve banbury <banburys@sonic.net>]

Hello "Statewid"--

You don't indicate whether you want to do CCD or film
imagery.
Since you're posting on APML, I'll assume you want to do film.

My advice would be to listen to Tony, Gene, and others who recommend
NOT using a separate guidescope with your SCT. Being obstinate (or
just
plain stupid) I kept going against this sage advice, and spent several
years
trying alternatives to the off axis guider.  

I never got an untrailed image for exposures longer than 10 to 15
minutes.

I have an object lesson example of what you can expect to achieve if you
don't heed this advice. Take a look at my STV thru GEG guided M51
image
on the following URL. You can click on it to see a larger image scale.
Next follow the link at the bottom of the page to the link  labelled
"Images made
with the C11 and STV" and again look at  the image of M51.This
shot was 
guided using the STV through a 76 mm  f7.4 TeleVue Oracle. 

http://www.sonic.net/~banburys/C11andGEG/

You might get better results with a separate guidescope---but I doubt
it!

Good luck--Steve

At 11:20 AM 10/16/02 -0400, 
Statewid wrote:
>I am using a Meade 10" LX200 with a Taurus off axis guider. I
want to begin 
>using a rear cell mounted 6.3 focal reducer but a good guide star is
not 
>attainable with that setup.
>So I'm looking into a guide scope instead. I currently own a Vixen
guidescope 
>- 70 mm,  400 mm focal length @ f5.7. Since my telescope with the
reducer 
>will be operating at 1600 mm, will this guide scope be properly
matched to 
>reduce trailing, or should I add a 2x barlow first to increase to
focal 
>length in front of my ST-4?
>Will this be enough focal length?
>Any other suggestions?
>
>
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