Re: [ATM] Ghosts in the Coulter

["Stephen Koehler" <s.c.koehler@gmail.com>]

Tim,

On 5/16/07, Tim Hager <thager6164@earthlink.net> wrote:
> I missed the beginning of this thread but this looks like pinched or warped
> optics to me.  How are the primary and secondary mirrors mounted?  Are
> either of them glued or too tightly pinched in their mountings?

It seems unlikely to me that a pinched primary or secondary would
cause this problem.  Both the primary and secondary on a Coulter are
sufficiently thick that the deformation imparted by pinching would be
relatively smooth deformations.  That doesn't agree very well with
multiple, relatively sharp, ghosts.

David,

If the ghosts are caused by eyepiece internal reflections, that can
easily be tested by using a different eyepiece, or by rotating the
eyepiece in the holder.

I'm wondering if your eye has been eliminated as the cause?  When I
look at a bright object, like the moon, without magnification I see
multiple, overlapped, images, due to astigmatism.  This could be
tested by switching eyes, or by asking another observer to describe
what he sees.
-- 
Steve Koehler
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