Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  NGC 2841

Image of the day 03/27/2022

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    NGC 2841 | With The Outer Dust Rings, Kevin Morefield
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    NGC 2841 | With The Outer Dust Rings

    Image of the day 03/27/2022

    Getting plate-solving status, please wait...
      NGC 2841 | With The Outer Dust Rings, Kevin Morefield
      Powered byPixInsight

      NGC 2841 | With The Outer Dust Rings

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      Description

      NGC 2841 is a massive galaxy 46 millions ly distant.  Wikipedia notes that it is home to a large population of young blue stars, though the blue does not show up in the arms as we usually expect.  Wikipedia also notes that few HII emission areas are seen, indicating little star formation is happening.  The core is decidedly reddish-yellow and in the surrounding disk I see clumps of material that is not the magenta of HII regions but more of a faint purple.  I'm curious if this is a mix of older red stars with the young blue stars they mention.  At first I assumed this reddish galaxy was in a haze of dust like IC 342, but maybe this is the actual color of the galaxy.   To be sure it is an unusual galaxy.

      The galaxy is surrounded by two or more faint, extended rings and a trail of material runnng from the top to the right in the image here.  This can be difficult to see but is easier with some of the extreme stretches I did initially.  The 8' size is nearly doubled when these outer rings are considered.  I did not do any burning, dodging other invasive treatment to show the rings, only curves adjustments to try and better show them.   The result is demure at best

      The full FOV contains some very bright blue stars which added a challenge to preserve the faint rings while flattening the glow from these stars.  Compositionally, I decided to crop them to create a more interesting image.  But the full frame with the bright stars is interesting as well.  I've added the full frame view here as well.

      Color calibration was done with PCC in PI.  This worked well and gives me confidence that the galaxy is correctly colored or at least very nearly so.  HDRMT was used to add contrast to the bright core and better display the knots on the arms.  But I reduced the effect by using 8 layers in HDRMT to keep things from going too far.  DBE was used to flatten the glows of the bright stars but I also used GradientXterminator in PS later to remove some residual glows after saturating the colors.  

      Because my goal was to represent the outer dust rings, I used every half decent Luminance sub I had and then also did a SuperLuminance with the RGB data.  This produced a FWHM of 2.8" which is not great for the galaxy detail.  So I went back and culled the Luminance subs to produce a sharper, FWHM of 2.25" version for the galaxy proper.  These two were combined with a mask in PS.  Noise reduction was applied to the background via a luminance mask in PS.  

      I shot a little Ha but it only confirmed the fact that there is little HII emission in the galaxy.

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      • Final
        NGC 2841 | With The Outer Dust Rings, Kevin Morefield
        Original
        NGC 2841 | With The Outer Dust Rings, Kevin Morefield
        C

      C

      Title: Uncropped nearly compete version

      Description: Uncropped but mostly processed

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      NGC 2841 | With The Outer Dust Rings, Kevin Morefield