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Globular cluster M13 (NGC 6205)

Katafraht
52930
Category:Deep Sky
Published:
2418
Globular cluster M13 (NGC 6205)NGC 6205NGC 6207IC 4617
Resolution:
5292x4258 px
File size:
23915 KB

Technical information

Telescope/Lens
Sky-Watcher Quattro 8CF
Camera
QHY163C
Mount
eq6Pro
Guide Scope
SVBONY 60/240
Guide Camera
QHY QHY5L-II-C
Accessories
televue paracorr 2"
Software
APT, PHD2, Pixinsight
Location
Московская область, Руза, Россия

Light pollution

Orange, Bortle 6 zone

Date taken

Exposure

  • 60 × 30″ · ISO/Gain: 0 ·
  • 60 × 60″ · ISO/Gain: 0 ·
  • 60 × 180″ · ISO/Gain: 0 ·

Total exposure: 4 h 30 m

Comments

Smirnov Andrey
Good shot, but the channels are misaligned. This is clearly visible from the "tails" extending to the right and down from the brightest yellow stars.
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KatafrahtReply to Smirnov Andrey
I still can't figure out the reason for such channel misalignment... the camera is color, after all.
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Smirnov AndreyReply to Katafraht
Indeed! I didn't notice that. Did you process it channel by channel, by any chance?
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Smirnov AndreyReply to Smirnov Andrey
It seems the issue is with the coma corrector. I just looked at the image channel by channel at high magnification, and the stars in the blue channel look like torn donuts. Nevertheless, the channels align well in Photoshop.
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KatafrahtReply to Smirnov Andrey
No... I only extracted the luminance for deconvolution, and then recombined it through LRGB combination.
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KatafrahtReply to Smirnov Andrey
No... I only extracted the luminance for deconvolution, and then recombined it through LRGB combination. Yeah, the corrector seems decent... I had the same issue with Baader too... Could it be due to the backfocus not being fully adjusted?
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Smirnov AndreyReply to Katafraht
It doesn't look like a streak; it's actually close to the center of the frame.
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KatafrahtReply to Smirnov Andrey
Then I'll try tweaking the deconvolution parameters in PixInsight... that's probably where the issue is coming from.
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Smirnov AndreyReply to Smirnov Andrey
Hmm... I was thinking: how was the camera oriented? By any chance, is that elongation not vertical? If so, it looks like atmospheric dispersion.
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KatafrahtReply to Smirnov Andrey
90-degree orientation...
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KatafrahtReply to Smirnov Andrey
Yes...the seeing was poor and the object was low above the horizon.
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