M81 - Bode's Galaxy

[jase]

Hi All,
Back to business after reprocessing a few entries especially for CWAS and shipped them off over the weekend. (Man, getting colour accurate pro prints done is expensive, especially on fine art paper!). Anyway, I’m pleased to present my latest offering, M81 - Bode’s Galaxy (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=152&fld_album_id=12)

First discovered by Johann Elert Bode in 1774, the grand spiral galaxy M81 (aka NGC3031 or Bode’s Galaxy) is one of the nearest galaxies outside our local group. It is the largest galaxy in a group of 34 galaxies located in the constellation Ursa Major. M81’s gravitational interaction with nearby galaxy M82 has increased its blue starburst and pink HII regions, stripping matter from M82. M81 resides approximately 12 million light years away.

About the image (the blurb for those interested);
The image is a LRGB composition with a total exposure time of 1.6 hours (Lum: 40min; R,G,B; 20min respectively). It was acquired through GRAS3 (TOA-150, ST10XME). Usual drill regarding calibration (bias, flats, darks) along with hot and dead pixel removal in MaximDL. Registered in Registar and combined (Sigma Reject) back in MaximDL. Luminance layer passed through three interations of RL deconvolution in CCDSharp. Tried to go great than 3, but the PSF results were not good enough. Needs more data to undergo a better decon run. On the topic of data (considering its peanuts worth and it screaming for more), there was heavy usage of noise reduction to get image looking aesthetic. I used three noise reduction masks of varying intensities to give the best control over bright and dim region noise – background is still noisy imho! This worked well even though time consuming. Colour balance appeared ok after needing to weight the blue channel by .6 compared to the other channels. Not sure why this occurred, but the background ADU was certainly lower. I’m happy with the saturation as it provides a natural feel. There is a misalignment problem on some stars which resulted in some heavily saturated greens and reds. This was resolved using the healing brush tool set to colour mode – not ideal. Some desaturation of the stars also completed the task. Used the SCM process to highlight the dark lanes, and then reduced the SCM layer opacity to 45% to keep a natural, unprocessed look. Minor adjustments to colour balance – raised the blue shadow +3 and red highlights -5. Think the black point could have been raised a few more points… Seasoned to taste.

Those northern hemisphere folks have all the great galaxies. We've got the nebs.:D

Hope you like it.:)

[jase]

Sorry all. My gallery has mysteriously gone offline. MySQL probs. Will bring online asap.:doh:

[Bassnut]

Excellent colour and a good sense of proportional scale. I often see M81 with unaturally large artifacts within the galaxy that immediately looses the scale grandness that a huge galaxy deserves. The effect presented here is most appropriate. Yes, I rely on decon to tighten up too, but found hrs of exposure time was needed to be able to use 30-50 iteratons without artifacts and noise over the whole image. The Ken Crawford videos you posted are excellent at selective processing, using a mix of say 2 images at 30 and right up to 150 iterations with layer masks (I guess thats what you mean by your 3 reduction masks, or was that only for noise processing?)

Thanks Jase, almost "gendler" in its smoothness ;-).

[jase]

Back online now. Whoa, nasty. MySQL isn't my strong point.

[monoxide]

i don't know how you do it Jase,
thats a fantastic image especially for 1.6 hours of data

[jase]

No, thank you Fred.;) I used three layer masks purely for noise reduction. Simply duplicate the original image three times and apply different strength noise reduction on them. Apply a mask to each so that it is easier to select which areas you want heavy or light noise reduction applied. The heavy noise reduction layer results in considerable detail loss which is fine for the background, but need to be masked to keep the highlights. I often get carried away at extracting every ounce of detail. Sharpening through what ever process you choose is great if you've got the data to handle it. If not, go the other direction and smooth it. I need much more imaging and image processing time under my belt to compare to a Gendler or Crawford. These guys are imaging machines.

[jase]

Thanks TJ. Not overly hard. I rework the same data over and over again until I'm happy with. Takes some patience/frustration and helps to have a method/process to work with. I'm sure if you went back and processed some of your images, you'd probably find new ways of extracting more from your data. Its trial and error, but don't be afraid to experiment.

[monoxide]

i'm still trying to wrap my head around a lot of the processing techniques, i just cant seem to get the results i'm after but the data i have isn't exactly fantastic to experiment with (short subs from an unmodded dslr with bad gradients)

[seeker372011]

jase

I sort of followed what you did till you got to the SCM bit...
huh?could you please explain as an (in)famous politician once said

oh and big to differ about northern hemisphere having the best galaxies, we got the Magellanic Clouds they dont :)

[EzyStyles]

fantastic shot as always jase. colours are nicely done. When did you capture the data? hasn't it been pouring rain from your neck of the woods? your not that far away from me and its been cloudy for the past 4 weeks!.

[jase]

Nothing like a challenge TJ. I don't like dealing with gradients!



SCM...Selective Contrast Masking

When you're close to the end of your image processing routine and have flatten all layers, do the following.
Create a new layer by dragging background layer to new layer icon in the layers pane (duplicate it in other words).
Optionally, name the new layer. I typically call it SCM
With the new layer highlighted, go to Filter > Other > Hipass (~6 pixels) - experiment here. 5 or 6 does it for me.
Switch layer mode from normal to overlay
Now create a layer mask for the SCM layer - This is very important. You might think the overlayed SCM looks pretty good at this point as its done some tricky "stuff" to the image, but watch what it does to your stars and noise etc. Not nice. Hence you need to create a mask to selectively highlight regions/details.
Layer > Add layer mask > hide all
select brush tool B
use brush (white) to selectively unhide areas in the mask
use brush (black) to revert to hidden if needed
Once satisfied – Layer Flatten Layers and save
Enjoy!You can obviously alter the opacity of the SCM so your images don't look too "plastic". Be careful you don't over do it.

The above was taken from a previous post of mine. Search is a wonderful thing.

Hmmm. Not sure re galaxies. LMC and SMC are irregular in shape and don't show much structure compared to M31 and others. Hmmm tough call.



Thanks Eric. The joys of remote imaging. It can be hailing where you are, but its bound to be clear somewhere in the world. http://www.global-rent-a-scope.com. Don't think my South Gippsland dark sky observatory would be able to image targets in Ursa Major anyway.:lol:

[JohnG]

Another beautiful photo, Jase, I will have to borrow some of that patience off you :).

Cheers

John G

[leon]

Totally agree, yea It's not bad, I suppose, :lol: :lol:, sorry Jase just fooling around, seriously now, it is a beauty, you seem to paint master pieces each and every time, some very professional work indeed. ;)

Leon :thumbsup:

[richardo]

Hey Jase,
excellent image considering how low it would be in your sky.
Here it doesn't even get a look in, down below the horri.

For the time invested you sure pulled some nice detail out.
Lovely colour and an almost silky appearance to the overal galaxy.
This is one of my favourite galaxies the northerners have.... swines!.
I'd love to get onto some of those in Draco and Ursa Major, but we do have Eta and Omega, plus many others they can't get to :D

Ah ha, so that's what you're up to.... getting pro prints done.
Sure beats the crap out of my A4 Glossy PP on a $65.00 Canon printer I send off :rofl:

Seriously, with some of the stuff you've been doing, considering you don't own an Astronomy shop with all the go gear :rolleyes: , ;), surely that will raise David M's eye brows.

All the best Jase
Rich

[strongmanmike]

Very nice indeed Jase. You really are acumulating a nice selection of images from all over the sky :thumbsup:

Mike

[Alchemy]

link not responding 8.21 am Wednesday 21st.

i will come back later.

[jase]

Cheers John. Appreciate the kind words:) Waiting for some more ST4k posts...:whistle:



:lol: Thanks Leon. Nothing like a bit of processing to soothe the soul (or stress you out and leave you scratching your head as to why it turned out like so!).;)



Hi Rich,
Thanks for the comments. It was taken remotely from the pristine dark skies of New Mexico in the US. No way could I collect it down south. I think the layer masks for noise control worked reasonably well on this target. Something different to the usual two step approach I do - heavy noise reduction on background, then a lighter one over the entire image so the background gets two iterations.

Yes, the fine art prints were done on a Canon 44" 12 colour pigment printer - spells expensive. The prints were down scaled to meet the CWAS size requirements. I spent a lot on digital proofing the work to ensure the colours were right, even though the RIP was quite accurate at converting Adobe RGB to CMYK profiles - I didn't trust it! The colour representation isn't perfect, but close. I'm reasonably happy with the results. I may upload the reprocessed panel being present on the website in due time.
A few of the digital proofs I have were glossy. I don't like the finish for astrophotos (my opinion). Matte or satin is my preference.

Not sure if I'll get a "look in" this year. There was plenty of great images last year. I didn't enter last year as my work in my opinion was sub optimal. Nearly didn't enter this year for the same reason. I know I can do better. Thanks again Rich. Look forward to seeing your entries.



Cheers Mike. Yes, the collection is progressively growing. No Messier imaging marathon, but some interesting targets none the less. Thanks again.



Sorry Clive. Web hosting provider grief. It appears to be now back online. This was not related to the mySQL problem earlier, just coincidental.

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Thanks all.:)

[Garyh]

Excellent result Jase!
Glad that out broadband is up and running again to look at the big version!
No real sign of blooming at all and the image has that natural feel to it as it hasn`t been processed much at all!
Thats a sign of good processing.
cheers Gary

[Alchemy]

Indeed a lovely image jase one of the nicest galaxies ive seen,
Shame its not visible from our part of the world

clive

[Ric]

Fantastic Jase, I like the feeling of depth in this image in the way that the spiral arms draw you into the centre of the galaxy.

Very enjoyable indeed.

[jase]

Cheers Gary. Pleased you can see the images that bit quicker with broadband. Indeed, I think I've got blooms under control (think!).



Thanks Clive. Yes, it is a shame, but I guess that's what remote imaging is all about. Thanks for checking it out, sorry it was not accessible before.



Cheers Ric. I didn't push this image very hard. The data simply wouldn't permit it. A reasonable result that I'm happy with. Thanks again.

[Kirkus]

My goodness! How beautiful is that? Just stunning!

[RB]

I'm in awe Jase !!!

Absolutely stunning my friend.

:)

[jase]

Thanks Kirkus. Something up your neck of the woods. You should try nail it sometime. Thanks again.



Thanks RB. Pleased you liked it.:thumbsup:

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Thanks all for your kind words.:)