Celestial hemisphere:  Southern  ·  Constellation: Sagittarius (Sgr)  ·  Contains:  B85  ·  M 20  ·  M 21  ·  NGC 6514  ·  NGC 6531  ·  Sh2-30  ·  Trifid Nebula
M 20, John R Carter, Sr.
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M 20

Acquisition type: Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)
M 20, John R Carter, Sr.
Powered byPixInsight

M 20

Acquisition type: Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)

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Description

Just experimenting with a CLS filter.

M 20 reached midheaven just as the Moon was coming up.

Stacking and processing in SharpCap, final touch-up with Affinity Photo.

Using a gain of 50 in SharpCap was unintentional, I thought it was set to 10. Some later experimenting indicates that a gain of 40 might be better. A lower gain means a longer exposure. Long exposures can saturate the pixels and lose the color in stars. I’ve yet to find the “sweet spot” for gain/exposure for a given object.

The image is cropped to eliminate the amp glow around the edge of the image - a problem with CMOS cameras.

I’m going to try the same image again without the CLS filter and different gain/exposure settings.

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M 20, John R Carter, Sr.