Re: [APML] Precise alignment of a 500 mm lens and a guidescope

["Matt BenDaniel" <matt@starmatt.com>]

Emmanuele,

You'll want to be able to adjust the aim of the guide scope by at least a
degree away from the center of the camera's FOV.  This will enable you to
both compose your picture and choose a good guide star.  If desired, you
can easily align the two instruments in the field by centering the lens on
a bright star, then adjusting the guide scope to be centered on the same
star.

I prefer the over/under configuration for guiding.  Although it may also
provide less opportunity for flexure, the main benefit (over side by side)
is that it is much easier to balance in DEC.  See photo here:
http://starmatt.com/gallery/equipment/130.html

Does the guide scope have a movable primary (for focus)?  Do you have a
reliable mirror lockdown?  If not, it may not be a good choice for a guide
scope.

Matt


Emmanuele Sordini said:
> Hi everybody,
> I'm having a machinist build a custom aluminium platform + dovetail for
> my  GM-8 mount. It's meant to house a 500 mm Pentax telephoto lens
> (quite  hefty!) and a 1000 f/10 MTO catadioptric lens for guiding.
> Here come the questions:
>
> 1) Anybody know of any smart way of aligning the two optics so as to
> avoid  any flexure?
> 2) Are there any quick methods (es. pre-aligning the whole rig at home)
> to  decrease, if not eliminate, the hassle of carefully setting it up in
> the field?
>
> Any advice/link/whatever is considered useful will be much appreciated.
>
> Thanks in advance,
> Emmanuele Sordini

-- 
Matt BenDaniel
http://starmatt.com


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