Re: [APML]: Beginner Needing Advise

[Steve Bell <sb635@delphi.com>]

Philip Perkins wrote:
> 
> The 201XT is a bit prone to "double track" - ie. recognise another star in
> the FOV and, if the first star drifts off a tad, hop over to the other star
> and resume guiding on that. This can lead to "double stars" in the image.
> To avoid this, you need to be aware of the guiding box limits in the
> reticle eyepiece FOV, and try to pick a solitary star within this box (other
> stars that are very much fainter shouldn't be a problem).
> 
> Other than these things, the 201XT works pretty smoothly and flawlessly
> with the LX200 and the results can be first class. Out of a total of about
> 50 shots (all on film) I've got about 12 that I'd rate as "perfect" (stars
> are precision pin-pricks - can't really be improved upon) and about 20 that
> look fine, but high magnification reveals a slight defocus / minor tracking
> error (sometimes difficult to tell which). The remaining 18-ish are
> double-starred, wind-blown, jarred, dewed-up, etc.
> 

Phillip, do you know how big (in pixels by pixels) is the guiding box for the 201XT? I 
can't imagine it uses 
the *whole* CCD, because that would be terribly inefficient.

What type of guidance exposure did you use on the 201XT for your successfull prime focus 
shots? What size LX200 
do you have?

-- 
Clear skies,
Steve Bell
sb635@delphi.com
http://people.delphi.com/sb635 - Astrophoto page