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Re: [APML] Televue 102 on G-11
At 10:16 AM 2/27/01 -0800, steve banbury wrote:
>At 12:26 PM 2/27/01 -0500, John Boudreau wrote:
> >snip
>
> Having said that, I still love my TV85, but these
> >scopes are primarily designed as visual scopes. The only model currently
> >made by TeleVue that's has one eye on photography in mind from the beginning
> >is the current TV101 and it's predecessors (Genesis and Genesis SDF) which,
> >being Petzval optical designs, have a built in field flattener. But all of
> >these TV scopes cry out for a 2.7" focuser.
>
>I have a related question.
>I've been considering moving away from my C8 to a refractor.
>But, when I look at whats available in the less than $2K range, most of the
>respected names have focal lengths less than 1000 mm.
>For extended objects like M8 it seems the image will nicely fill a 35 mm
>frame when used with
>something like a TeleVue Genesis.
>
>But--how does one obtain images of small objects like M57 for example when
>using something
>like a TeleVue Genesis SDF having a focal length of something like 540 mm?
>Scan the image, and blow it up? Use a teleconverter? Keep the C8?!!
Steve,
It is hard to photograph faint objects using a system slower than f/12,
so there's a limit to what you can do with a teleconverter or barlow.
I agree with John; keep your C-8 for planetary nebulae, planets and other smaller objects.
For objects like M42, the f/6.3 reducer doesn't really help the C-8 get the right FOV.
You might have to settle with using the smaller instrument and fine grain film.
>Steve
>
>
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