Re: [APML] Guidescope / set-up question / Thanks!!!

["bert katzung" <katzung1@home.com>]

Hi Aike:

Some responses to your comments:
>
> >There is certainly no sense in trying to
> >optically align the guidescope with the celestial pole or anything else.
The
> >mount is what has to be aligned, and you should do that with the imaging
> >scope, NOT the guidescope.
>
> I think I didn't explain this correctly - I meant the alignement between
the
> photographic and the guiding scope - I thought they have to be perfect
aligned
> to each other (besides the polar alignement of the mount).
>
> Is this not needed ??? - could the guidescope be 1 - 2 degrees of the
> photographic instrument (when alignement of the photographic scope is
perfect),
> I thought that I would receive "trails" on my image?!?

That's right, it is not needed. The big advantage of a separate guidescope
vs an off-axis guider or built-in second guide chip is that you have a much
larger selection of guidestars. If you are too far off from the imaging
scope you will start to get trailing (as Matt pointed out), but 1 to 2
degrees is probably acceptable. Furthermore if you are using something like
an ST-4, you can't limit the guidescope axis very much or you won't be able
to center the guidestar on the very small ST-4 chip.

>
> >I would suggest getting a pair of good heavy
> >rings of the Losmandy type (I use 125 mm rings) and Losmandy plates, make
> >sure every thing is snugged down good and tight, and stay with the
refractor
> >guidescope.
>
> Losmandy rings sound like the most recommended solution from all of the
> replies, even though they are very pricey, so many people can't be wrong!
Do you
> know how they can be combined with the Vixen rings, I have in my R200SS?

If you can place a Losmandy plate across the top of your Vixen rings, you're
all set: the rings have dovetail blocks that clamp onto a standard Losmandy
male dovetail plate. Alternatively, use
the Losmandy side-by-side plate with the R200SS on one side and the
guidescope (on a Losmandy dovetail plate) on the other.

Bert

Bert Katzung
katzung1@home.com
www.astronomy-images.com



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