Hemisphere:  Northern  ·  Constellation: Coma Berenices (Com)  ·  Contains:  NGC 4712  ·  NGC 4725  ·  NGC 4747
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NGC 4725 & NGC 4747 | The One Arm Galaxy, 



    
        

            Kevin Morefield
NGC 4725 & NGC 4747 | The One Arm Galaxy
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NGC 4725 & NGC 4747 | The One Arm Galaxy

Getting plate-solving status, please wait...
NGC 4725 & NGC 4747 | The One Arm Galaxy, 



    
        

            Kevin Morefield
NGC 4725 & NGC 4747 | The One Arm Galaxy
Powered byPixInsight

NGC 4725 & NGC 4747 | The One Arm Galaxy

Imaging cameras: QHYCCD QHY600M

Mounts: Paramount ME II

Guiding telescopes or lenses: Planewave CDK14

Guiding cameras: Starlight Express UltraStar Mono

Software: CCDWare CCDStack 2  ·  CCDWare CCDAutoPilot 5  ·  Adobe Photoship CC  ·  PixInsight

Filters: Astrodon Blue  ·  Green  ·  Red  ·  Luminance


Dates:March 5, 2020

Frames:
Astrodon Blue: 19x600" (gain: 56.00) -10C bin 1x1
Green: 17x600" (gain: 56.00) -10C bin 1x1
Luminance: 28x600" (gain: 56.00) -10C bin 1x1
Red: 20x600" (gain: 56.00) -10C bin 1x1

Integration: 14.0 hours

Darks: ~20

Flats: ~20

Bias: ~20

Avg. Moon age: 10.03 days

Avg. Moon phase: 76.72%

Bortle Dark-Sky Scale: 3.00


Astrometry.net job: 3308388

RA center: 12h 50' 51"

DEC center: +25° 36' 54"

Pixel scale: 0.304 arcsec/pixel

Orientation: 237.181 degrees

Field radius: 0.454 degrees


Resolution: 9080x5759

Locations: Sierra Remote Observatory, Auberry, California, United States

Data source: Own remote observatory

Remote source: Sierra Remote Observatories

Description

This is one of the most beautiful galaxies in my opinion and should be seen more often. The larger galaxy, NGC 4725, features a single, graceful arm and interacts with its neighbor NGC 4747. This interaction is heavily distorting the smaller galaxy. It appears to me that there are two loops of dust and blue stars both toward and away from the larger galaxy. On the left, 150 million light years futher distant, NGC 4712 spins unaffected.

This is my first complete image with the QHY600M. I used Read mode 1, called high gain mode, and a gain of 56. This setting provides a low read noise of 1.683e and a full well of 21,657. That full well may not seem very large, but when you consider the area of the 3.76 micron pixel it is 5.73 times smaller than a 9 micron pixel. So the full well is about 24% larger than my 16803 over the same area. So I've chosen to use the same exposure times per sub here - 10 minutes. I have tested 15 minute luminance on another galaxy and this appears to work well.

I did not bin. Given the generally bad Winter seeing, I gained nothing by not binning, and of course was over-sampled. I wanted to see how this data looked and processed at this pixel size as I may get some benefit during the best Summer seeing. That of course is debatable and remains to be seen!

Luminance sub FWHMs here ran from just below 2" up to 3". I would like to have continued acquiring better Luminance data but clouds intervened and I want to move on to some further tests with new objects.

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NGC 4725 & NGC 4747 | The One Arm Galaxy, 



    
        

            Kevin Morefield

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