Re: [APML] Strange Star Artifacts in Takahashi FSQ-106N Image

["Chris Cook" <ccook@cape.com>]

Hello Wade -

I have a FS102 and get the same artifact on bright stars.  I posted the same
type of question here on the APML about a year ago and the consensus
(although not a 100% sure answer) was that the three silver objective
spacers on Tak refractors, they are in the light path, are creating this
artifact.

Here is a shot of Jupiter & M44.  Note the effect on Jupiter.

http://www.abmedia.com/astro/dsc2/m44-jupiter.html

This seems to only happen on Tak refractors.  A-P scopes do not use these
spacers.

Chris

-----------------------------
Chris Cook Photography
www.cookphoto.com


----- Original Message ----- 
From: "Thomas W. Earle" <twade@bmi.net>
To: <astro-photo@seds.org>
Sent: Saturday, February 19, 2005 5:27 PM
Subject: [APML] Strange Star Artifacts in Takahashi FSQ-106N Image


> I recently got all my Comet Machholz images back from development.
> They turned out really well.  I'll have them scanned probably in the
> next month or so.  In the interim, I discovered that my Takahashi
> FSQ-106N has a problem with bright stars.  I have included the
> following link for people to look over.
>
> http://www.northwest-landscapes.com/html/StrangeStars.html
>
> Does anyone have any idea what could be causing this strange
> phenomenon?  The "radial shadows" appear to "rotate" with the field
> of view.  For example, the shadow in the lower left star of Orion's
> belt is oriented southwest to northeast, the middle star's "shadow"
> is oriented west to east, and finally the upper right star is
> generally northwest to southeast.  It is very strange indeed.  Could
> I have a bad field flattener?  Has anyone else experienced this
> strange behavior with bright stars?
>
> Thanks in advance,
>
> Wade
>
>
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>
>


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