The area around M81 and M82, captured at SRO between Nov 2014 and Jan 2015. I have tried to make the IFN (Integrated Flux Nebula) the main feature of the image for better or worse
I find these dusty images particularly difficult to process and I have done a few versions already. Feedback is appreciated as always.
Scope: FSQ-106ED
Mount: Paramount ME
Camera: QSI683
Filters: Astrodon Gen II LRGB
Guiding: QSI OAG + Lodestar
Image scale: 2.094 arcsec/pixel
Exposures: 48x900s L, 20x900s R, 14x900s G, 16x900s B (24.5 hours)
Processing: PixInsight 1.8
It is a crazy yet magnificent field this one and I think you have done a commendable job here Rick and I am glad you decided to emphasise the dust at the expense of the slightly brighter/lighter/noisier and consequently slightly washed out colours. The Galactic Cirrus just looks so cool
I know what you mean by finding these galaxy and dusty fields hard to process, I think I had similar difficulty with my NGC 5068, 5084 field in southern Virgo year before last. There was just so much cool looking galactic cirrus in the field when it was stretched but the noise became excessive, getting the stretched dust to match in with the galaxies naturally without too much noise and consequently obvious noise reduction as well as the washed out colours effect creeping in, was very difficult and I was never really happy with it.... so I did two versions to have the best of both Worlds .
Well done again on a deep image of an area most of us southerners have never had the privilege of imaging.
You've just convinced me that there really is such a thing as interstellar medium, even far from the Milky Way, and it isn't just artifact of processing. All very well reading about it in the textbooks. Congratulations.
It is a crazy yet magnificent field this one and I think you have done a commendable job here Rick and I am glad you decided to emphasise the dust at the expense of the slightly brighter/lighter/noisier and consequently slightly washed out colours. The Galactic Cirrus just looks so cool
I know what you mean by finding these galaxy and dusty fields hard to process, I think I had similar difficulty with my NGC 5068, 5084 field in southern Virgo year before last. There was just so much cool looking galactic cirrus in the field when it was stretched but the noise became excessive, getting the stretched dust to match in with the galaxies naturally without too much noise and consequently obvious noise reduction as well as the washed out colours effect creeping in, was very difficult and I was never really happy with it.... so I did two versions to have the best of both Worlds .
Well done again on a deep image of an area most of us southerners have never had the privilege of imaging.
Mike
Thanks very much, Mike. I have another really dusty one to process. Must strike while the iron is hot
Quote:
Originally Posted by ghsmith45
Magnificent Rick. Amazing to think that 30 years ago nobody knew all that stuff was out there.
Geoff
Thanks, Geoff. Yes, it's amazing what we can produce with relatively modest equipment these days. I remember when galaxies were just dim blurs seem with averted vision!
Quote:
Originally Posted by Placidus
You've just convinced me that there really is such a thing as interstellar medium, even far from the Milky Way, and it isn't just artifact of processing. All very well reading about it in the textbooks. Congratulations.
The faint nebulosity is definitely real. I just grabbed some archive IR survey data from the WISE mission at 12 microns (Band 3) near M81 which matches your image pretty well.
A great image Rick although I think you need to clean your filters!
My god, I've seen other images that show the dust but wow, that is like a mist and its even haloing the bright stars like a mist would.
Greg.
Thanks, Greg. A halo effect from the IFN is a very interesting idea. The FSQ-106/QSI-683 combination does produce halos around bright stars so it could partly be due to that. I'll see if I can find some subs from an IFN-free area with similar brightness stars to compare.
Quote:
Originally Posted by Tony_
Fantastic image - it's amazing what is out there that can only be seen with superb images like this!
Tony.
Thanks, Tony.
Quote:
Originally Posted by Paul Haese
That is bloody awesome. Superbly processed with lots of cirrus and cool detail in both galaxies. Excellent work Rick.
And thank you very much, Paul!
Quote:
Originally Posted by SamD
Yes, wonderful work !
The faint nebulosity is definitely real. I just grabbed some archive IR survey data from the WISE mission at 12 microns (Band 3) near M81 which matches your image pretty well.
I have tried to make the IFN (Integrated Flux Nebula) the main feature of the image for better or worse
Rick.
Very beautiful, Rick.
In addition to the IFN, existing in this field is also quite a lot of tidal material which has been drawn out of some of the galaxies by interactions between them. For instance, in this Ultraviolet image from GALEX, you can see some knots of OB stars which are a long way from M81. I have seen these blue knots, though very faintly, in some Very Deep amateur images made with standard CCDs:
The difficulty of finding faint extensions of the galaxies in this field, in the optical regime, must surely be to distinguish genuine features from the IFN.
Have you or any of your imaging colleagues any way of subtracting out the IFN from images? It would have to be accurately subtracted from an image in order to leave only those features which are at the distance of M81/M82...... as a residual image.
In this thread, SamD has found a nice 12 micron image of the field, which may facilitate in subtracting out the foreground nebulosity; in order to isolate only the tidal material between the galaxies.
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Quote:
Originally Posted by Placidus
You've just convinced me that there really is such a thing as interstellar medium, even far from the Milky Way, and it isn't just artifact of processing..
It sure exists.....just take the same star cluster with the same mix of stellar spectral classifications and put it a couple of thousand light years away; then it looks perceptibly redder due to effects of submicron-sized dust particles that permeate all the space between the stars.
But it took a long time for astronomers to become convinced of the existence of a diffuse medium of dust that relatively evenly permeates our own Galaxy. Here is the first of the two 1930 discovery papers by
Robert Trumpler: http://articles.adsabs.harvard.edu/f...ASP...42..214T
Another thing that exists between the stars of spiral galaxies is a faint diffuse H-alpha nebulosity.... which is simply gas that has been caused to gently glow by the radiation field of a galaxy. Some amateur Ha images are deep enough to detect the diffuse H-alpha emission between the stars, e.g. this one by Mike Sidonio: http://www.iceinspace.com.au/forum/s...t=91067&page=2
Those galaxies with a large population of young blue massive stars can have prominent H-alpha emitting nebulosity throughout the entire galaxy, for instance here is an H-alpha image of NGC 4945;
My eyes have been opened in more way than one, never knew there was so much intergalactic fog there
Thanks, Dunk. The IFN is still associated with our galaxy but it's definitely in the outer suburbs.
Quote:
Originally Posted by madbadgalaxyman
Very beautiful, Rick.
Thanks for the interesting discussion, Robert. I don't know of any obvious way to subtract the IFN but it would be interesting to think about. I'll have a look at highly stretched versions of the different colour masters to see if there are any interesting differences.
Quote:
Originally Posted by ozstronomer
Beautiful Image Rick, i really like your processioning of the IFN, well done
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