Celestial hemisphere:  Southern  ·  Constellation: Sagittarius (Sgr)  ·  Contains:  B85  ·  HD164225  ·  HD164402  ·  HD164492  ·  HD164514  ·  HD164637  ·  HD164704  ·  HD164717  ·  HD164739  ·  HD164833  ·  HD164844  ·  HD164864  ·  HD164883  ·  LBN 27  ·  LDN 232  ·  M 20  ·  M 21  ·  NGC 6514  ·  NGC 6531  ·  Sh2-30  ·  Trifid Nebula
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M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB, Rowland Archer
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M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB

Getting plate-solving status, please wait...
M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB, Rowland Archer
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M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB

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Description

The Trifid is one of my favorite objects - I really love the red/blue contrasting colors.

It's pretty low in my sky and I had to catch it for the couple of hours it's visible between trees.

I really need to tweak my horizon files - the first 30 minutes were shot with the Newt pointing half above the observatory roof line, half below!

Acquisition spanned 8/9 to 9/15 over 11 nights. Funny, doesn't seem like we had that many decent nights over that period.

Stacked in APP, which did a nice job of blending my rotated light frames (camera came loose and spun around to a new position one night!). Also removed gradients and stacked HaRGB with APP. I like APP's newer channel combination feature - the presets and sliders make it quite easy to play with combinations. I ended up just adding the Ha to the R channel to boost the main nebula.

Did remaining post-processing in PI. PCC, MLT NR, Decon for the L frame, Arcsinh and masked stretch, LRGB Combination to add the L. Curves, HDRMT, Dark Structure Enhance script. Despite the low altitude for this target, didn't feel the need for any NR in the non-linear phase.

Then over to Photoshop for some star reduction on the big bright guys using Croman's StarShrink with a large radius to not shrink the smaller stars. Finished in 3D LUT Creator, a very cool tool (thanks Lloyd!) that lets you click on any color in the image and drag to affect the color intensity and hue for that color across the field. Selective Color on steroids with a large dollop of ease-of-use.

Had fun with this one, been gathering data and not processing for a few months. Good to see a result .

Comments

Revisions

  • M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB, Rowland Archer
    Original
  • Final
    M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB, Rowland Archer
    B

B

Description: A bit lower brightness

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M20 - Trifid Nebula - M21 Open Cluster - TS ONTC Newtonian - LHaRGB, Rowland Archer