This image represents the pinnacle in one of my imaging chapters – image scale amalgamation i.e. successfully combining data acquired at different focal lengths. Most importantly, this project prompted the redevelopment of some processing techniques that I had thought about, but never acted on until now to deliver a pleasing end result. I have explained parts of the process below. So, without further ado, I’m pleased to present M83 – Southern Pinwheel Galaxy.
The Southern Pinwheel Galaxy (M83) is located in the constellation Hydra and is a member of the Centaurus group of galaxies which includes peculiar radio galaxy Centaurus A (NGC5128). M83 is classified as a between a normal and barred spiral galaxy based on its characteristics. The immense spiral structure of the arms contain various blue and red knots of star clusters and diffused gaseous (HII) regions respectively. M83 is the southernmost galaxy in Messier’s catalogue and resides approximately 15,000 light years distant.
About the image (for those interested);
This image is an LLRGB composite totalling 6.1 hours (Luminance:100min;RGB:90min each). The luminance data was acquired from GRAS008 – 12.5” F/9 RC operating at ~2800mm. The Chrominance (RGB) data was acquired using the FSQ-106ED 4” F/5 Petzval APO operating at 530mm. As one could image, we are dealing with vastly different image scales. The chrominance data was solely to be used for colour information on the high resolution luminance data. Calibrated all frames – usual process. Firstly, I worked on the luminance. Excellent data was obtained from the RC (10x10min subs) shooting the target while it was +80 degrees (no AOL used here!). Very slight gradient present which was removed using GradientXTerminator, then continue with a multi strength deconvolution blend to bring out the details. Minor background noise removal in NeatImage. On to the chrominance - from past experience, upscaling of any data requires good quality data to ensure noise isn’t introduced into the image. I dedicated an imaging run solely for RGB, collecting 90min in each channel (6x15min subs). In the past, I’ve found that simply upscaling the chrominance to match the luminance gave strange results, in particular with the stars (due to the considerably large difference in image scales). So to counter act this, I first downsized the hi-res luminance to match the low-res RGB chrominance. The two were blended using lighten mode, blurred, boosted in colour saturation and flattened. This new image had become the superRGB chrominance frame which I then upscaled to match the luminance frame for final composition. The end result provided a greater improvement on star matching and colour correction. The luminance was layered twice so I could bring back the colour hues while keep detail. Minor noise reduction performed on the chrominance layer. Star halos subtly accentuated using colour masking. Image flattened, before final selective noise reduction. Seasoned to taste. The shear number of faint fuzzy galaxies that dot the background is impressive in the full res version.
I’ve also imaged its northern counterpart M101, which can be viewed here. Though I think this version needs some colour balance work considering it was processed on a old laptop, not a calibrated monitor (which I now have access to).
The full size image presented (2400x1800) is a 75% image size reduction of the total image. The 100% is remarkable – will use this for prints. The crop shows M83 slightly offset to show the brilliant blue star (HIP 66549 – spectral class F2III/IV). I’ve attached TheSky imaging plan to provide an insight into the composition planning along with some background PGC galaxies. I composition is actually incorrect as the instrument rotator should have been at 168’, instead of 186’ shown. However, I still found a guide star that allowed for 7sec exposures!
I hope you enjoy it as much as I did processing it! As always, all comments welcome.
I'm going to recommend you for a position as an observer once JCU gets its 1m scope and observatory up and running. For an amateur, that is a remarkable piece of work!!!!. Well done!!!!.
I'm going to recommend you for a position as an observer once JCU gets its 1m scope and observatory up and running. For an amateur, that is a remarkable piece of work!!!!. Well done!!!!.
You should be doing a higher degree in Astronomy.
Thanks Renormalised. It would be my absolute pleasure to get my hands on some quality data from a 1m class scope for image processing. Even if you simply feed me quality monochrome luminance data. I'll find away of processing it! Seriously though, if you're looking to perform some collaborative work, just let me know.
Quote:
Originally Posted by EzyStyles
i have seen alot of images of M83. That is seriously the BEST i have EVER seen!. Jase, takeover the Malin award.
The Hi Res version is stunning. i stilll have abit of saliva around my mouth.
Cheers Eric. Malin award! Actually, this image is unlikely to be in the panel I'll present this year. Of course, I can't give too much away
Absolutely brilliant Jase. The clarity, detail, colour balance, smoothness and the number of background galaxies clearly defined makes this an absolutely brilliant image Jase.
By combining the data from the different focal lengths you certainly reached that pinnacle.
Absolutely brilliant Jase. The clarity, detail, colour balance, smoothness and the number of background galaxies clearly defined makes this an absolutely brilliant image Jase.
By combining the data from the different focal lengths you certainly reached that pinnacle.
Thanks Barb and David. I certainly put the hard yards into this image. Will be honest, the stars still caused me some grief with the upscaling of RGB data so took some work to bring back the aesthetics. I feel I still managed to keep the image looking natural. Thanks again.
Quote:
Originally Posted by iceman
OMG that is absolutely magnificent.
Truly stunning, Jase. What an inspiration.
Cheers Mike. Appreciate the kind words. As they say, once bitten by the imaging bug, you're poisoned for life - there is no return from the dark side. Seriously, I did find the data scaling challenging especially at the focal length difference we are talking about. Seems to have come together quite well.
Quote:
Originally Posted by Peter Ward
Jase,
A benchmark image for sure. Nothing not to like here! Well done
Cheers
Peter
Thanks Peter. Any chance of getting some time on that 14" RC of yours? Not sure if I'm happy dealing with the light pollution gradients though (such a waste of quality gear - I have a dark sky site in Gippsland if you want to ship your gear) Actually, I may soon have access to a 14" RC in WA, 20" and 24" RC's in the US from lightbuckets.com - Steve is still bringing things online. I'm getting edgy to nail some targets with either the 20" or 24". Should boost my imaging output and experience. Surely there are clear night skies somewhere in the world!
Quote:
Originally Posted by bloodhound31
Truly Beautiful Jase, gives us all something to aspire to.
Blessings,
Baz.
Cheers Baz. Keep at it mate, we all have goals to work towards. Make them realistic and you'll succeed. Thanks again.
What can I say? It is a real credit to you. The actual imaging is always secondary to the result, processing is where it happens.
Well done.
Darn right Gary. The workload is 20%-30% acquiring the data, 70%-80% processing it. Once you've got the data, you need to know what do to with it. Mask the defects and highlight the good detail. Sounds simple, but in practise not always easy. Don't be afraid to try something different. Once you've got a few routines that work well for you, stick with them - but then add some tasks to extend and/or challenge yourself. Thanks again for your comments.
Quote:
Originally Posted by dugnsuz
The large version is stunning jase - well done, a fantastic result.
Doug
Thanks Doug. The large version is a 75% reduction! The full frame (3900x2600 - 100%) is a visual treat.
Fantastic image Jase. Even just reading the notes lets me learn something re being able to mix FL's. Just looking at it encourages me to get out there and capture some of my own images.
Tastefull colour balance on the M83, a pleasing view. The M101 is a tad blue, and looks like some blue fringing on the brighter stars. I think youll find G8 now has external guide. Ive taken flat runs at Morrook on as my task, so if you have a problem with them please advise.
As always, all comments welcome.
Actually, this image is unlikely to be in the panel I'll present this year. Of course, I can't give too much away 
Actually, I may soon have access to a 14" RC in WA, 20" and 24" RC's in the US from lightbuckets.com - Steve is still bringing things online. I'm getting edgy to nail some targets with either the 20" or 24".
Should boost my imaging output and experience. Surely there are clear night skies somewhere in the world!
