NGC 6946 - The Fireworks Galaxy - Mono LRGB Version
Date: September 23, 2020
Cosgrove’s Cosmos Catalog ➤#0054
NGC 6946 as captured by my Astro-Pysics/ASI1600MM-Pro system (click image for full resolution via Astrobin.com)
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About the Target
NGC 6946 - The Mono Camera Version.
Known as the Fireworks Galaxy and Caldwell 12, this object is a face-on spiral galaxy on the boundary between Cepheus and Cygnus' constellations. It is located 25.2 Million Light years away and is about 1/3 of our own Milkyway Galaxy size.
The Annotated Image
An annotated image of NGC 6946 was created using Pixinsight’s ImageSolver and AnnotateImage Scripts.
The Location in the Sky
IAU/Sky & Telescope Constellation Map of Cepheus with NGC 6946 marked by the yellow arrow.
The Imaging Project
During the past few nights, I revisited this target, and I shot it with two Telescope simultaneously. In one, I used a One-Shot-Color Camera, and in the other (This one), I used a Mono camera with L, R, G, &B filters. I wanted to see the difference I would get with both approaches.
The OSC version resulted from 130 frames of 150 sec for a total exposure of about 5.5 hours. The mono version had roughly the same level of exposure with 46 subs of 120 seconds for the L, R, G, &B filters for a total of about 6 hours.
As it turns out, I had a parameter set wrong, and the images ended up being rotated 90 degrees from one another. Despite that, please take a look at both of them and tell me which one you like better.
Updated Comments 7-26-21 (as I publish this into the website):
The two resulting images from this test are very similar and one conclusion that can be made is that you can get about the same results on both systems. Having said that, I find that I prefer the Mono version image a bit more - the galaxy arms seem to have a better definition and more of a 3D form to me. Most others that have weighted in here would tend to agree. In the end, I think it is a preference call. Having said that, you are also looking at some other differences in these images which is likely impacting your preference. The Mono image has a slightly larger image scale and the background sky was made darker in this image. These factors may well have had a larger impact on your preference than whether it was OSC vs Mono.
The OSC version of the Image. (click to zoom)
The Mono - LRGB version of the image. Which do you like better? (click to zoom)
2019 version of the Fireworks Galaxy (click to zoom)
As a comparison, here is the very first version I ever shot, in September of 2019.
The post for the image is HERE.
Some progress for sure!
Capture Details
Light frames
45 x 120 seconds, bin 1x1 @ -15C ZWO Gen II L Filter
45 x 120 seconds, bin 1x1 @ -15C ZWO Gen II R Filter
45 x 120 seconds, bin 1x1 @ -15C ZWO Gen II G Filter
45 x 120 seconds, bin 1x1 @ -15C ZWO Gen II B Filter
Total integration time: 6.0 hours
Cal Frames
50 Bias exposures
25 x120 seconds Dark exposures
50 L Flats
50 R Flats
50 G Flats
50 B Flats
Capture Hardware
Scope: Astrophysics 130mm Starfire F/8.35 APO refractor
Guide Scope: Televue 76mm Doublet
Camera: ZWO ASI1600mm-pro with ZWO Filter wheel with ZWO filter set
Guide Camera: ZWO ASI290Mini
Focus Motor: Pegasus Astro Focus Cube 2
Mount: Ioptron CEM60
Polar Alignment: Ioptron Ipolar integrated alignment cameras
Software
Capture Software: PHD2 Guider, Sequence Generator Pro controller
Image Processing: Pixinsight, Photoshop, along with Coffee, extensive processing indecision and second-guessing, frequent processor's regret, significant frustration, and the occasional swear word...…..
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