M64 - Black Eye Galaxy
Messier 64, Black Eye Galaxy (slight crop) - Click here for full resolution
The Black Eye Galaxy is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices. It was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier the next year. A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the "Black Eye", "Evil Eye", or "Sleeping Beauty" galaxy. The interstellar medium of Messier 64 consists of two counter-rotating disks that are approximately equal in mass. The inner disk contains the prominent dust lanes of the galaxy. The stellar population of the galaxy exhibits no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde orbit, or the continued accretion of gas clouds from the intergalactic medium. It has a diameter of 53,800 light-years.
source: Wikipedia
NGC/IC:
Other Names:
Object:
Constellation:
R.A.:
Dec:
Transit date:
Transit Alt:
NGC4826
Sleeping Beauty Galaxy, Evil Eye Galaxy
Galaxy
Coma Berenices
12h 56m 43.7s
+21° 40′ 57.57″
14 April
58º S
Conditions
M64 is a typical target for the spring ‘Galaxy Season’ and reached altitudes of almost 60° at my location at the time of imaging. It is located in an area with lots more Messier galaxies, a busy area of the sky. Images were taken from the backyard in Groningen, The Netherlands during the month of March 2022. The moon was largely absent in the later parts of the night, which allowed for some decent SQM values for this location of 19.6-19.7.
Equipment
This image is taken two years before it was actually processed and published on this website. At the time of imaging, the original rig from the observatory was used for this image. This includes the Takahashi TOA-130 1000mm refractor on a 10Micron GM1000 mount with the ZWO ASI1600MM Pro camera. Even though the field of view of this setup is not super big, the galaxy is still a relatively small object in the field.
Telescope
Mount
Camera
Filters
Guiding
Accessoires
Software
Takahashi TOA-130, FL67 flattener, Sesto Senso 2
10Micron GM1000HPS, Berlebach Planet
ZWO ASI1600MM Pro, cooled to -25 ºC
Astrodon 1.25” LRGB mounted, ZWO EFW 8-position
Unguided
MacMini (Intel), MacOS Mojave, Pegasus Ultimate Powerbox v2
KStars/Ekos 3.5.7, INDI Library 1.9.4, Mountwizzard4 3.0.0, PixInsight 1.8.9-2
Imaging
Realising that there was not a whole lot of colour to be collected, the focus was on collecting as much luminance signal as possible. Overall 12.5h of exposure was collected of which 8.7h luminance. Looking back at the diary from those sessions, they were not without their challenges, as is more often the case with a mobile setup like this. Some initial unbalance, excessive dithering and a partially successful meridian flip all required their own attention to ensure imaging went on and high quality images were collected.
Resolution
Focal length
Pixel size
Resolution
Field of View
Image center
4308 × 3296 px (14.2 MP)
1002 mm @ f/7.7
3.8 µm
0.78 arcsec/px
56' x 42’
RA: 12h 56m 45.480s
Dec: +21° 40’ 57.28”
Processing
All images were calibrated using Darks (50), Flats (25), registered, integrated and normalised using the WeightedBatchPreProcessing (WBPP) script in PixInsight. Processing followed a pretty standard pattern. There had been some heavy dithering in the images, so the edges were quite rough that had to be cropped away using DynamicCrop. Gradients on all individual integrated stacks were removed using GraXpert.
The colour channels were combined, calibrated using SPCC and stretched using GHS, with 70% colour blend to ensure colours would remain somewhat vibrant. Noise was removed using NoiseXTerminator (NXT). While NXT did a great job, colours were just smeared out just a little bit more using a convolution step, so that absolutely no noise would be introduced from the RGB image. The structure comes from the Luminance image anyway.
The luminance followed a similar pattern, but instead of colour calibration, a deconvolution step was applied here, to bring out as much as detail as possible. That detail is mostly present in the eye of the galaxy, as the arms don’t show very little structure. Using several small iterations of GHS, an attempt was made to pull out some small differences in shade, but the effect of this was very subtle. Also the luminance image was treated with some noise reduction from NXT.
Bringing the luminance back into a somewhat convoluted colour image is always a rewarding step, and this was no exception. It was felt that the blue-ish hues could get a little boost, and rather than change the whole image, a simple GAME-generated mask was used to apply the extra blue saturation only to the galaxy. A final increase in contrast using CurvesTransformation, and adjusting the background level to the default 0.07 completed the processing.
Processing workflow (click to enlarge)
This image has been published on Astrobin and received Top Pick status.
