Casitas de Gila, Gila, NM
April 10 - 14, 2021

Reprocessed 2/7/2023

During my April 2021 astrophotography trip to Casitas de Gila, Gila, New Mexico, I imaged M63 (NGC 5055), the Sunflower Galaxy in the constellation Canes Venatici (the hunting dogs).   I captured Luminance, Red, Green and Blue filter subframes over four nights, with M63 being the first of three targets done each night.  Conditions varied between good seeing to poor transparency with high clouds.  The Jet Stream flowed overhead from West to East, degrading the seeing.

Description:

M63 is a spiral galaxy, type Sbc.  It has a patchy spiral pattern with many short arcs instead of well-defined arms.  The grainy, circular patterns give a sunflower like appearance.  There is also a very extensive inter flux nebula surrounding the galaxy with only a small halo shown in this image. M63 is about 29 to 37 Mly from Earth, and it has a diameter of almost 100,000 kly.  M63 is a part of the M51 galaxy group. (SkySafari 6 Pro)

Original Processing:

Color processing in PixInsight was a challenge for this galaxy.  Up to this point, I have used local normalization or adaptive normalization with good success.  However, the red, green, and blue channel images were altered significantly when adaptive normalization was used in the Integration tool.  I could not get the colors correct and there were color artifacts in the combined RGB image.  When I integrated the color stacks without normalization, the color calibration produced a better result.  However, I could not get the spiral arms to be bluer without affecting the core.  The ColorMask script also failed me this time.  Once again, the stars are bloated and have chromatic aberrations that I cannot explain when using an SCT that was well collimated and an imaging train that used threaded connections.

Reprocessing 2023:

I continued my effort to reprocess most of the image data sets that had flaws and issues using new PixInsight tools and an improved workflow.  Again, Russ Croman’s XTerminator tools made a significant difference in improving the imaging and simplifying the workflow.  For M63, reprocessing went smoothly, but for one issue.  The bright star on the edge of the galaxy did not separate properly with StarXTerminator in the stretched state for both luminance and RGB color images (linear state star removal was worse).  This galaxy would also benefit from Hydrogen-alpha data to pick up emission regions.

Imaging details:

Celestron 9.25" Edge HD SCT with off-axis guider (FL = 2350mm, f/10)
Celestron CGEM II mount
ZWO ASI 1600MM Pro cooled monochrome camera (-15C)
ZWO 36mm Luminance, Red, Green and Blue filters

Software:    Sequence Generator Pro, PHD2 guiding, Celestron CPWI mount control,
    PixInsight and Photoshop CC 2021/2023

Luminance    2 min x 126 subframes (252 min), Gain 139, Offset 21, 1x1 binning
Red     4 min x 36 subframes (144 min), Gain 139, Offset 21, 1x1 binning
Green    4 min x 27 subframes (108 min), Gain 139, Offset 21, 1x1 binning
Blue    4 min x 35 subframes (140 min), Gain 139, Offset 21, 1x1 binning

Total integration time: 10.7 hours