Re: [APML] Internal Reflections with a JMI focuser on my SCT.

["Richard Crisp" <rdcrisp@earthlink.net>]

----- Original Message -----
From: "Bryan & Kristin Bradley" <bradley3@optonline.net>
To: <astro-photo@seds.org>
Sent: Monday, January 12, 2004 4:16 PM
Subject: [APML] Internal Reflections with a JMI focuser on my SCT.


> I'm wondering if anybody has any thoughts or ideas of why I'm getting
> internal reflections (bright arcs) since incorporating a JMI NGF-S
focuser.
> I have a 1600mm SCT(10" f/6.3), and am now getting these bright arcs in my
> timed exposures from bright stars outside my 35mm field.  I definitely
have
> the internal light shield which came with the NGFS focuser which is
supposed
> to correct this issue.  By removing the focuser I have obviously
eliminated
> the issue.  But I'd really like to use the focuser due to mirror shift
> issues in my SCT.
>
> Any help would be appreciated.



Flock the inside (best) with flocking paper or spray paint it flat black
inside. Anodizing is quite reflective.

I had the same problem with my Optec TCF-S and my 2" nosepieces.

With the steeper light cone of the focal-reduced SCT I think that will
aggravate the problem.

I used some of the self adhesive Kendrick Flocking paper,. Worked great for
me.

Good luck
Richard

>
> Sincerely,
> Bryan Bradley
> http://bryanbradley.com
>
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