Re: [APML] 5.5" Schmidt Woes

["tan@home.com" <tan@home.com>]

John,

    You're making me paranoid <g> If my Schmidt ever gets out of focus, I think its
game over. I have never focused one before and the thought of attempting this
iteratively is pretty intimidating. Thanks for the advice, I might very well apply
some sort of removable rubber cement over my centering screws, just in case. Maybe
you can convince Kevin to perform the focus for you, just one last time. A focused
Schmidt is quite an amazing instrument, especially with Tech Pan. The stars on the
negatives are microscopic.

Loke


"John C. Mirtle" wrote:

> Thanks Robert, Bobby and Dave;
>         As the 5" Schmidt isn't equipped with a filtered film holder, so I will
> follow up the lead for Newport Glass. First, I want to get it collimated. It
> is unfortunate that no-one has filled the gap left by Epoch. I'm sure that
> my Schmidt isn't the only one around that needs tweaking. I also know Peter
> from when he lived in Alberta in the '80's and I agree with Dave - this
> isn't the thing to catch his attention.
>         Dave - Celestron's Schmidts are actually very adjustable. Too adjustable
> for my liking. You can change the centering of the corrector plate. (Just a
> few millimeters) The film holder is also adjustable for centering. This
> appears to be a weak point in their design. On both my 8" and 5" Schmidts,
> these centering screws have been loose. I would recommend that anyone with
> the Celestron design epoxy these grub screws in to place, before they work
> loose and you lose collimation. The film holder distance to the primary can
> be adjusted for focus, but only by someone braver than me. Finally, there
> are 3 collimating screws on the primary. I guess it's time to get the
> wrenches out, or I will never catch up with Loke..... Thanks guys!
>
> John Mirtle
> Calgary, Ab. Canada
>
> -----Original Message-----
> From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
> Behalf Of Bobby Middleton
> Sent: Sunday, September 30, 2001 7:45 PM
> To: astro-photo@seds.org
> Subject: Re: [APML] 5.5" Schmidt Woes
>
> ---- Original Message ----- > And finally - has anyone stumbled across a
> 5.5"
> > > Hydrogen-alpha filter, W92 or W25? Thanks!
> >
>
> Browse here John to see if they have something close.
> http://www.newportglass.com/schott.htm
> Bobby Middleton
>
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