Re: [ATM] More on aperature stops

["Nils Olof Carlin" <nilsolof.carlin@telia.com>]

Arjan,
>>.  The larger smear is
>> indicative of scattering, poor baffling, and a bad eyepiece that's
> ghosting on you (could be a poorly cleaned eyepiece).
>>

> I saw the same effect (though not as bad) looking at Mars, and concluded
> that my scope needs some more anti-scatter measures. I would have expected
> the same effect to happen when watching the moon, but the terminator and
> edge appear razorsharp, using exactly the same setup.
> This puzzles me, what else than scatter could cause the halo?

One possibility is reflections within the eyepiece and eye - at least the
eye isn't multicoated!. I have seen this - a large, well-defined and
homogeneous halo around bright planets, but I haven't been able to pinpoint
the cause. But the distinct edge, also shown on the sketch, does not look
much like scatter.

N O


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