Re: [APML] piggy back guide scope size

[Alan Voetsch <critter12952@yahoo.com>]

--- Larry McManus <lmcmanus@clearpointadv.com> wrote:
> Can anyone give me a minnimum size for a guide scope
> to go on my sc. I have
> a 6 x 6 Hasselblad connected to the visual back of
> my 8" sc and I need to
> come up with a setup to allow me to guide on long
> exposures.

Hey Larry,

Kent's right. Because of the moving mirror in SCTs,
you are best advised to use an OAG, like a GEG or
Taurus T III. You could be guiding away perfectly
through a guidescope and there can still be any number
of ways that your shots will be wasted. Flexure,
mirror rotation, focus shift, OTA contraction due to
falling temperatures. Guidescopes on a SCT are a
crapshoot.

Alan

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