Celestial hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  M 63  ·  NGC 5055  ·  Sunflower Galaxy
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M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
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M63 Sunflower Galaxy (CVn) in LRGB

Getting plate-solving status, please wait...
M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
Powered byPixInsight

M63 Sunflower Galaxy (CVn) in LRGB

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Acquisition details

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Description

Physical Details

This is M63, the Sunflower Galaxy, in Canes Venatici (CVn). It is a famous flocculent spiral galaxy first discovered by Pierre Mechain, later verified by Charles Messier on June 14, 1779. Lord Rosse was first to observe the spiral structure using his 72-inch Leviathan, publishing his findings in 1850.

There is an excellent, detailed write up of this galaxy in Annals of the Deep Sky, vol. 3, by Jeff Kanipe and Dennis Webb. I refer to just a few of the interesting facts here. This is a fairly large and bright galaxy of size 12.6' x 7.2' and magnitude 8.6, classification SA(rs)bc.

The patchy (flocculent) structure breaks up the spiral arms, making them hard to follow even in higher resolution images than mine. They are thought to be comprised of star-forming regions of massive clumps of molecular gas with varying rates of rotation. Early measurements of the proper motion of points within the structure proved difficult to obtain, but later measurements were made up to a small distance from the core. There are high surface-brightness spiral arms in the central region that spiral outward. In the case of M63, these are abruptly interrupted about 50" from the center. The inner region has a maximum rotational velocity of 206 km/s, with dynamics dominated by luminous matter, where the outer part beyond the main stellar disk declines to about 25 km/s and remains constant beyond., with dynamics thought to be dominated by a dark matter halo.

Not visible in my image is a warped, gaseous disk that extends beyond the main bulk of the galaxy towards fainter nearby galaxies. Those more interested in these structures are encouraged to read the section in the Annals book I cited above.

Just barely visible in my image is UGCA 342, the diffuse structure seen to the right of M63. This is most recently catalogued as a Megellanic irregular, however SIMBAD and others still list it as a galaxy (follow the previous link). It is part of the M63 system and may be responsible for causing, disturbing and gobbling up part of the diffuse tidal streams I mentioned above.

According to the M63 Wikipedia article, it has a redshift of 484 km/s, distance 29.4 Mly (8.99 Mpc).

Acquisition, Imaging and Processing Details

This is the second image that I've posted from my most recent imaging session in which I had to contend with high winds. Interesting, the first image was of NGC 2841, another flocculent spiral, so I inadvertently had a theme going those nights. I am much more pleased with the outcome of this image than the previous, partly due to having obtained more integration time, but also due to efforts I've been making to improving my processing.

I encourage you to look at the other Revisions as well as the Final Image, which is a closer crop of the fuller FOV obtained at F10.

Deconvolution in PixInsight has always been a bit of a mystery to me, but lately I've been diving into Warren Keller's Inside PixInsight, 2nd ed., and much of the murkiness of the process is starting to be cleared. This is a more pleasing outcome.

Additionally, I've been working harder to unsharpen my stars through later processes, and generally I like the outcome here, although next time I'll dial it back a bit. I use both Convolution and MorphologicalTransformation on the non-linear Luminance to smooth out the edges of the stars as well as to decrease their size a little bit. Through these steps I smoothed out the sharp edges of the stars that resulted from the Deconvolution step as well as a gentle application of UnsharpMask, and this allowed the color to come out better.

Another change I made with this processing was using a less sharp mask during the noise reduction steps. I realized that there was benefit to allowing a small gradual amount of noise reduction to happen on the brighter parts of the image, so the mask was made to be more tapered than I've done in the past. I liked the outcome of this.

One last thing I'd like mention is that I posted an image of M63 two years ago using the same equipment but also with my Celestron 0.7x Focal Reducer in place. One doesn't notice small, gradual changes as they happen, but looking back at the quality of my work from two years ago has given me a warm satisfaction that I am indeed improving. Frankly, today I would never publish an image as noisy and over-sharpened as the previous one, but I'll keep it uploaded as reminder to me to keep moving forward ...

I hope that you enjoy this write-up as well as the image. Your comments and suggestions are always welcome.

Comments

Revisions

  • Final
    M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
    Original
  • M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
    E
  • M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
    F
  • M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
    G
  • M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah
    H

E

Description: LRGB Image - This shows the fuller FOV from my F10 C11 + QSI 683-ws8 imaging system.

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F

Description: Luminance Image - This image better shows the flocculent structure of M63.

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G

Description: Inverted Luminance Image - From this image it is a bit easier to locate UGCA 342 to the right of M63 as well as to discern more of the halo, which is harder to see in the LRGB image. Several small, distant galaxies can be spotted here, particularly a group below M63.

Uploaded: ...

H

Description: Annotated LRGB Image - PixInsight's AnnotatedImage script did a good job spotting brighter features in the image, but it is not the tool (yet) for marking those small, distant background galaxies.

Uploaded: ...

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M63 Sunflower Galaxy (CVn) in LRGB, Ben Koltenbah

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