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Observing >> Deep Sky Observing

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GlennLeDrew
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Oddity in m8 lagoon nebula new [Re: Tyranthrax]
      #5976052 - 07/17/13 01:55 PM

Based on that, one of the better possibilities is direct light from an angle off axis which shines directly through the corrector and into the primary baffle, resulting in scatter. But to get this highly structured kind of flaring implies at least a semi-specular reflection, if not highly specular. This is more likely from some shiny (even black anodized) surface near the back end, not too far ahead of the camera.

It would be instructive to remove accessories and peer up into the rear opening from off axis. Can any direct view of the scene beyond be seen through a crescent-shaped gap formed by the primary baffle's innermost opening and the secondary baffle's visible edge? Even though such direct light may fall outside the field if view, this light can scatter off various and sundry inside surfaces not too far ahead of the focus.


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Tyranthrax
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Reged: 04/22/13

Loc: Reno, NV
Re: Oddity in m8 lagoon nebula new [Re: GlennLeDrew]
      #5977001 - 07/17/13 11:15 PM

I'll take a look, I'm pulling her out tonight to see what I can see out there tonight.

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GlennLeDrew
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Oddity in m8 lagoon nebula [Re: Tyranthrax]
      #5977350 - 07/18/13 07:20 AM

The test I suggested is best done in the daytime, or better yet, from the comfort of indoors. You are merely looking to see if a gap is seen between the baffle openings, allowing a direct sight line out through a portion of the corrector plate immediately surrounding the secondary. Conversely, looking through the front end would allow you to sight through the corrector, just outside the secondary, and look right through the primary baffle.

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