Firstly, to fully appreciate the depth achieved in this image, make sure you turn up the brightness on your phone, or ideally view on a computer monitor in a dimly lit room and adjust/increase your screen brightness appropriately, this grey scale can help. Please enjoy a surf around any of the Full Resolution versions linked to below.
Ultra Deep image of M83
This is an extremely deep image of the southern spiral galaxy M83 and immediate surrounds, in Hydra and is perhaps (?) even the deepest, as far as revealing extended diffuse features, that has ever been compiled of this galaxy, while also displaying the full dynamic range of the scene and in colour? The image shows a wealth of detail** across the galaxy disc and main spiral arms and both Halpha and OIII data have been included in the image to better reveal the extensive star forming regions across the galaxy. Generally considered an intermediate sized spiral, an extensive outer halo, that envelopes the galaxy out to over 24 arc min in diameter, has been revealed, this is approximately double the normally referenced apparent size of 12.5 X 10 arc min, for the galaxy. At the distance of M83, this apparent size equates to an actual diameter of over 110,000 light years. Not previously seen this clearly, subtle contrast enhancement applied to this halo has revealed it to be comprised of a number of very faint but distinctly separate, long spiral arms, that wrap around and envelope the galaxy. Also seen and first revealed by Malin and Hadley (1997) in deep amplified photographic plates, taken with the UK Schmidt Telescope at the Australian Optical Observatory, is a very faint outer stellar stream (bottom left), whose curve is closely concentric with and located somewhat distant from and north west of the galaxy.
**NB: No Blur Exterminator or other AI based sharpening was used on this data.
The data for this image was collected over six nights during April, May and June and on all but one of those nights, when the seeing bloated out for a couple of hours (not even good enough for RGB!), the seeing was most excellent, with the raw FWHM of the Lum frames, as measured in MaximDL, consistently ranging between 1.5" and 1.8" over the more than 27 hours of data collection, which is very helpful in preserving detail and acheive my goal of revealing some actual stellar resolution in the galaxy arms. I am convinced I need a finer image scale than 0.84"/pix, in order to take better advantage of such conditions...fingers crossed I can get some smaller pixels in the light path some day, for the good nights .
This high contrast stretch, reveals the full extent of the galaxy halo and confirms that the outer halo is likely also physically connected to the distant north west stellar stream.
Here is a link to an annotated version identifying the many peculiar star clusters and stellar nurseries found straying way out in the galaxy halo
Here is a composite of some of the many distant galaxies around M83
This paper by Barnes et al. provides some interesting insights into the structure and formation of M83 and the nature of the north west stellar stream.
Hope you enjoy
Mike
Last edited by strongmanmike; 05-07-2024 at 09:43 AM.
That is beautiful Mike. With that stream at bottom left shown so clearly could now be called "the rat tail galaxy". Well worth all those hours"work".
Cheers, Richard
Have you tried more dithering and drizzle perhaps Mike before going to a smaller pixel camera?
Amazing and inspiring work - thanks for sharing. Have just been "galaxy surfing" some of the other galaxies visible which are amazing in their own right too - the 2 larger ones in your thumbnail are really showing some nice detail.
Hi Mike,
that is a fantastic image.
27 hours and 30 minutes of integration.
L,Ha,OIII,R,G,B = 15hrs, 4.2hrs, 3.2hrs, 1.6hrs 1.6hrs, 1.75hrs.
You have really excelled this time.
As expected so many other distant galaxies have popped out.
That is beautiful Mike. With that stream at bottom left shown so clearly could now be called "the rat tail galaxy". Well worth all those hours"work".
Cheers, Richard
Thanks so much Richard, yeah it does look a bit like a rat or possum tail in this orienation huh? cool
Quote:
Originally Posted by joshman
Wow! Mike, that is stunning. Even more so to get that kind of resolution without the use of "AI" based sharpening routines.
Thanks Josh ma'man, who is soon to have a mount nearly as good as mine Gotta love AP mounts, when does it arrive? Yeah I see soooo few images that have used BlurEx where it isn't as obvious as DB's, that I just can't warm to it as a "look" the odd imager out there has managed to use it without being obvious but still get some benefit and those are ok I guess?
Quote:
Originally Posted by RobF
Have you tried more dithering and drizzle perhaps Mike before going to a smaller pixel camera?
Amazing and inspiring work - thanks for sharing. Have just been "galaxy surfing" some of the other galaxies visible which are amazing in their own right too - the 2 larger ones in your thumbnail are really showing some nice detail.
Yes the Drizzle thing has been suggested before Rob and I keep meaning to have shot at it...buuut seems I am a creature of habit ...besides, a finer physical image scale is better than drizzling, like better seeing always trumps RL decon, BlurEx or other sharpening
Quote:
Originally Posted by alpal
Hi Mike,
that is a fantastic image.
27 hours and 30 minutes of integration.
L,Ha,OIII,R,G,B = 15hrs, 4.2hrs, 3.2hrs, 1.6hrs 1.6hrs, 1.75hrs.
You have really excelled this time.
As expected so many other distant galaxies have popped out.
cheers
Allan
Thanks Al, yeah always a lover of seeing a myriad of background galaxies but it was the massive extended halo with spiral structure that made me swoon this time
Mike,
Wow !!
Excellent M83 with resolution and detail us mere mortals can only dream about.
Well done from the top of Australia
Also love the wide outer spirals beyond the main structure ( rarely exposed )
Glad to see you finally bit the bullet and joined Astrobin , a great hosting platform with loads of features ( my second year on it )
Mike,
Wow !!
Excellent M83 with resolution and detail us mere mortals can only dream about.
Well done from the top of Australia
Also love the wide outer spirals beyond the main structure ( rarely exposed )
Glad to see you finally bit the bullet and joined Astrobin , a great hosting platform with loads of features ( my second year on it )
Cheers
Martone
Cheers Martone I certainly could not find a single other image of M83, regardless of telescope size, that shows the full extent of the outer halo and with structural detail along with a clear north west arc and in full dynamic range colour but no problemo, happy to be shown one if there is one, be great to see, really
Yeah I bit the bullet and joined Astrobin, it has some nice features
Mike
Last edited by strongmanmike; 01-07-2024 at 09:45 PM.
Hi Greg, thanks a lot mate, imaging motivation has been lack luster this year, grief is a funny thing, very dynamic and changes perspectives a bit but I'm still enjoying getting up there, just in a less manic, must take advantage of every bit of clear sky time, sort of way, more chilled
Yes, there was plenty of OIII but I'm not sure it particularly added much to the image as I'd hoped? Some of the slightly teal tones in the central 50% of the main galaxy have been caused by this OIII.. I think?
Thanks Al, yeah always a lover of seeing a myriad of background galaxies but it was the massive extended halo with spiral structure that made me swoon this time
Mike
Hi Mike,
you're right and I see a definite place for long exposure images
taken with fast Newts. - extreme deep fields.
Nothing else seems to pick up those faint halos so well.
Is it Rolf Olsen who pioneered that?
NGC5128 with NASA data added showed us the way: https://www.rolfolsenastrophotograph...ld/i-XH3VRsC/A
Hi Mike,
you're right and I see a definite place for long exposure images
taken with fast Newts. - extreme deep fields.
Nothing else seems to pick up those faint halos so well.
Is it Rolf Olsen who pioneered that?
NGC5128 with NASA data added showed us the way: https://www.rolfolsenastrophotograph...ld/i-XH3VRsC/A
cheers
Allan
Rolf is a legend and yes I think his 120hr Cen A, completed back in mid 2013, illustrated the effectiveness of uber long exposures and may well have started the trend...now, some ten years on, there are whole groups of imagers combining efforts to compile amazing 200hr, 300hr+ exposures , that are revealing vanishingly faint features and have made numerous discoveries, it's almost a kind of magic Eventually there will be more of these collaborations and much, or all, of the sky will likely have been imaged in this manner..?
At 27.5hrs, my M83 is a mere token effort in comparison...but still, I'm happy with the outcome, my location helps
Nice capture of the outer arms of M83. I like the colour too. I remember reading about the outer arms a few years back now and wondering at the time if my GSO RC12 could capture it from my obs at Clayton Bay.
I do wonder what my 16" RCOS could capture at the altitude you are working from though.
Nice capture of the outer arms of M83. I like the colour too. I remember reading about the outer arms a few years back now and wondering at the time if my GSO RC12 could capture it from my obs at Clayton Bay.
I do wonder what my 16" RCOS could capture at the altitude you are working from though.
Thanks Paul
I'm currently at an image scale of 0.84"/pix, I'm confident the seeing quality I consistently see, would suit 0.42"/pix on many nights. My current telescope actually suffers from some astigmatism, not a huge amount but enough to mean my MaximDL measurements indicating the majority of my subs are sitting at 1.4"- 1.8" across the year, are actually more like 1.2"- 1.6" were my scope aberration free. It's actually annoying me, so yes, very confident a scope like your 16" or a smaller pixel camera on my scope, would definitely excel at high resolution imaging at Eagleview, the extra sampling could handle some more decon as well.
.
the odd imager out there has managed to use it without being obvious but still get some benefit and those are ok I guess? 
...besides, a finer physical image scale is better than drizzling, like better seeing always trumps RL decon, BlurEx or other sharpening 
but it was the massive extended halo with spiral structure that made me swoon this time 
