M81 and M82 through the mist

[RickS]

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

High res versions here: http://www.astrobin.com/full/169239/0/

Cheers,
Rick.

[clive milne]

30 years ago, that image might just have won you a nobel prize.

[IanP]

WOW .. this is jaw-dropping ..

[RickS]

Story of my life, Clive. I've got this great idea for a web search engine too :)



Thanks, Ian!

[strongmanmike]

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 :thumbsup:

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 :D.

Well done again on a deep image of an area most of us southerners have never had the privilege of imaging.

Mike

[Geoff45]

Magnificent Rick. Amazing to think that 30 years ago nobody knew all that stuff was out there.
Geoff

[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.

[Shiraz]

yep, that's a sobering image - looks like it wouldn't have taken all that much more density to cut off our view altogether!

re processing, that's a Herculean effort to get the dim background and still have some colour in the galaxies. :thumbsup::thumbsup:

[RickS]

Thanks very much, Mike. I have another really dusty one to process. Must strike while the iron is hot :)



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!



Thanks, Mike. There was no painting done at all ;)

[RickS]

Thanks, Ray! I do enjoy a processing challenge and I always learn something new. The thing I struggle with is when to stop :)

[gregbradley]

A great image Rick although I think you need to clean your filters!:rofl:

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.

[Tony_]

Fantastic image - it's amazing what is out there that can only be seen with superb images like this!

Tony.

[Paul Haese]

That is bloody awesome. Superbly processed with lots of cirrus and cool detail in both galaxies. Excellent work Rick.

[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.

[RickS]

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.



Thanks, Tony.



And thank you very much, Paul!



That's very cool. Thanks, Sam.

[Camelopardalis]

Whoah awesome Rick :thumbsup:

My eyes have been opened in more way than one, never knew there was so much intergalactic fog there :D

[madbadgalaxyman]

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:
180061

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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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/full/1930PASP...42..214T

Here is a good overview of much of the early work on dust in our galaxy:
http://articles.adsabs.harvard.edu//full/1988PASP..100..310S/0000310.000.html

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/showthread.php?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;
180060

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[ozstronomer]

Beautiful Image Rick, i really like your processioning of the IFN, well done :thumbsup:

[RickS]

Thanks, Dunk. The IFN is still associated with our galaxy but it's definitely in the outer suburbs.



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.



Ta, Geoff! Hope you're feeling better.

[Stevec35]

If your purpose was to image the IFN around M81 and M82 Rick I would say that you succeeded <g>. Very well done!

Steve

[RickS]

Thanks, Steve :)

[DJT]

Absolutely stunning. You see a lot of images framing these 2 galaxies but I had no idea there was all this stuff inbetween. Great stuff.:thumbsup:

[NOMH]

Are you sure a cotton ball didn't somehow explode over your objective when you were away from the scope?!?

That is a stunning image Rick. Great job and what they say about SRO skies appears to be true.

JB

[SamD]

Yes, sounds like a sensible thing to try. I'm not really sure what colour you would expect IFN or faint galaxy extensions to be. If the faint outer part of a galaxy is really just an extension of a spiral arm (like in the GALEX image), it would be blue, but if it is a result of tidal streams of ejected stars it might be white (like deep visual images of M51).

The IFN dust might behave like "normal" denser reflection nebulae. These are usually blue since they reflect light from nearby O/B stars. However, if the main source of light illuminating the IFN is the core of the Milky Way, you might expect it to be more yellow.

Might be worth noting, for a galactic latitude of 40, that there is a lot of dust in this region of the sky. The lower image here (a rectilinear projection with north at top) is a stretched total extinction map for the Milky Way. It shows a feature sometimes called "The Polar Spur" going across M81/M82. The upper image is zoomed in on M81/M82, showing some banded dust structures.

[multiweb]

Well done Mr. Misty. :thumbsup::thumbsup::thumbsup:

[marc4darkskies]

Whoa! :eyepop: That's so deep I think I have a case of the bends now!! :thumbsup:

[RickS]

Thanks, David.



Thanks, JB :)



I tried a few experiments doing PixelMath on the colour frames but no useful results yet. Most of the IFN appears in the Luminance and it's very faint in the colour subs so I suspect longer colour subs would be needed to pull out these faint signals.



Thanks, Marc!



:lol: Thanks, Marcus.

[SpaceNoob]

oh... damn... wow, someone turn on the fog lights, it's heavy tonight!

Far out... :eyepop:

[niharika]

Excellent image Rick. Looks even better with the lights out on a big monitor.

[alpal]

Hi Rick,
That is such a nice picture.
I would have been tempted to increase the colour very slightly with LAB mode -
with a mask for only the bright areas
& then increased the contrast very slightly for the overall picture.

cheers
Allan

[RickS]

Thanks, Chris :)



Ta, Raki!



Thanks, Allan. I did adjust the a* and b* curves but eventually decided to turn them down a little so that the IFN, which was my intended main subject, didn't suffer by comparison. Definitely a matter of personal taste...

[Ross G]

What an amazing and unique photo Rick.

The detail and depth is unbelievable!

One of my favourite photos...ever!

Ross.

[RickS]

Thanks very much, Ross!

[graham.hobart]

Astonishing really.
:eyepop:
Thanks for the view.
Awe inspiring.
Graz

[Rod771]

Sensational Rick! I've seen a lot of images of similar composition and you wouldn't even know all that dust is out there. You've done a great job showcasing it, well done! :thumbsup:

[rustigsmed]

amazing work Rick!

[RickS]

Thanks Graz, Rod & Russell!

[SkyViking]

Superb rendition of this particularly dusty patch of sky Rick, very nicely done! The IFN is looking stunning here, and the full resolution image is a delight to surf around in. Incredible how the fainter galaxies on the right side are almost drowned out by the dust.
I suppose the curious small star spikes are due to the ccd microlenses. I recall seeing a similar effect in some of my own, and others', deep images.
Thanks for the impressive view! :thumbsup:

[RickS]

Thanks Rolf! Yes, the spiky artifacts on the stars are from the KAF-8300 microlenses. They pop out even more if you do some size reduction on the stars. Now that I'm intimately familiar with them I can't unsee them. Just show me an image from a QSI-683 or STx-8300 or H-18 and I'll notice them :)

Cheers,
Rick.