Re: [APML] Suggested Astrophoto Accessories for Vixen VC200L

["westergren" <westergren@netzero.net>]

Allan,

The main difference between the 1-1/4 and 2 inch accessories for
astrophotography is the light path to the film (or CCD).  An off-axis guider
uses a prism or mirror to the side of the FOV to give the guider a star to
guide on.  The prism or mirror will create a shadow on the film, much more
on the 1-1/4 than the 2 inch. Also, the diagonal of a 35mm film is about 1.7
inch, so 1-1/4 inch would have serious vignetting.  These are the reasons
many astrophotographers have gone to 2.7 inch focusers and accessories (but
I don't think that's possible with the Vixen VC200L).

I have used the Lumicon Deep Sky filter with film, but I don't care for it.
It changes the color and requires longer exposures. It can allow photos of
objects in light polluted skies, but if you have dark skies, go bare.  Color
filters are used to create tricolor images with a monochrome CCD or hypered
Tech Pan film.  The quality and band-pass of those filters are significant
to determine the quality of the pictures.

Enjoy the views and the experience with your new scope.
Don


> Also - just so I understand,
> can someone briefly go over the benefit of 2" accessories compared to 1
> 1/4".  Additionally, are there any good filters I could get from
> Lumicon for nebulae photo's etc? Anything else I should put on my
> shopping list?
>
> Sorry for all the questions -  I appreciate the assist & once I get
> this stuff down I can start helping out the newbies down the road!
>
> Thanks,
>
> Allan Whetzel


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