Celestial hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  NGC 4485  ·  NGC 4490

Image of the day 06/20/2022

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    NGC 4490 and 4485 | The Starburst Bridge, Kevin Morefield
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    NGC 4490 and 4485 | The Starburst Bridge

    Image of the day 06/20/2022

    Getting plate-solving status, please wait...
      NGC 4490 and 4485 | The Starburst Bridge, Kevin Morefield
      Powered byPixInsight

      NGC 4490 and 4485 | The Starburst Bridge

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      Description

      Also known as ARP 269, this pair of galaxies are in the throes of a dance of life rather than death.  Floating above what looks like the last remnants of the spiral, we see active star forming regions that appear to bridge the gap between the two.  A line of Ha and OIII, mixed with the yellow-browns of dust, seem to wrap the larger galaxy.  A halo of dust surrounds both.

      This pair are nearby.  At only 25 million lights years, they are the same distance as M106.  In part this nearness drew me to the object as I felt I could capture these starburst regions in both Ha and OIII.  To isolate the Ha and the OIII information I subtracted the continuum red from the Ha and continuum green and blue from the OIII.  In the linear state I added the purified Ha data back to the red channel at 25% strength.  The purifed OIII was added to both the green and blue channels at 12% and 25% strength respectively.  I felt this method would preserve the red of the Ha and the teal of the OIII data without overwhelming the RGB.  I think this helps bring out the nuances of the starburst regions.

      To retain as much color in both the stars and the galaxy I stretched the HaOIIIRGB data with ArcSinh and then lightly a bit more with HistogramTransform.  A bit of color saturation was added prior to using LRGB combination to marry the SuperLuminance data and the color data.  I was careful to stretch the SuperLuminance data lightly so that it did not overpower the color data.  Brightening, contrast and sharpening were done after the combination.  

      Sharpening was done in CCDstack just because I really like that sharpening tool.  RC-Astro's NoiseXterminator tool was used through a luminance mask to concentrate the effect on the shadows.  

      I'll upload the pure OIII and Ha data as an HOO for your review.  I find this lasso of starburst connecting the two galaxies fascinating when isolated.

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      • Final
        NGC 4490 and 4485 | The Starburst Bridge, Kevin Morefield
        Original
        NGC 4490 and 4485 | The Starburst Bridge, Kevin Morefield
        B

      B

      Title: HOO

      Description: Narrowband Ha and OIII combo after removing continuum data.

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      NGC 4490 and 4485 | The Starburst Bridge, Kevin Morefield

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