Re: [APML] Polar alignment vs. flexure star trails

["William R. Mattil" <wrmattil@ix.netcom.com>]

Adam Krause wrote:

> Here is the picture that I took: 
> http://home.att.net/~krausefam/m13-100dpi.jpg 
> <http://home.att.net/%7Ekrausefam/m13-100dpi.jpg>


Adam,

Curious ...

>  
> I thought that if the problem was bad polar alignment, that the star 
> trails would rotate around the guide star, and that the guide star 
> would stay still (by the way the guide star is outside of the 
> picture), but in the picture I took, the star trails are not rotating 
> around the star I was guiding on.  The only reason I can think of for 
> this is flexure.


Not exactly ...... Movement of the optics can be a killer too. It might 
help to know what the primary instrument was and the guidescope ? SCT's 
and Newt's don't do guidescopes very well. Not with going to a lot of 
detail to secure the moving mirror (SCT) or the secondary (Newtonian).

>  
> Am I even right to think that a pure polar alignment problem (no 
> flexure problem) would cause everything to rotate around the guide star?
>
Exactly .....


You have either Mirror Movement or Secondary Movement, or ... Flexure.

Regards

Bill

-- 

William R. Mattil	:	http://www.celestial-images.com

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