View Full Version here: : Nebulae of the Octant
Hi All,
Thought I would sweep around the south celestial pole for some interesting features to image having heard the region contains some dust. What I was not expecting was to come across such a vast complex of dust. This is real Hoover material right here! So it goes without saying, I couldn't resist taking up the challenge of this rarely imaged area;
Nebulae of the Octant (http://cosmicphotos.com/gallery/image.php?fld_image_id=231&fld_album_id=9)
Warning: high resolution versions may take time to load.
Octans is the most southern of southern constellations devised by Nicolas Louis de Lacaille in the eighteenth century. It was named in honour of John Hadley's invention of a double reflecting octant. Astronomers and navigators used this scientific instrument to measure angular distance between the horizon and celestial objects. The constellation hosts the location of the south celestial pole. Unlike the north pole, it has no bright pole star. Sigma Octantis is the closest naked-eye star to the pole alas it is so dim it is difficult to use for navigation. The constellation does not contain many deep sky objects but makes up for it with a complex array of galactic cirrus dust clouds. The dust clouds are faintly illuminated by the energy released from the integrated flux of all stars in the Milky Way and are composed of dust particles, hydrogen, carbon monoxide and other elements.
Dark skies are key for this target. If you're up for a challenge, I recommend giving it a shot. Having produced a mosaic with similar galactic cirrus (MW9 (http://cosmicphotos.com/gallery/image.php?fld_image_id=179&fld_album_id=9) aka Sarah's Nebula for Mr Sidonio), I somewhat knew what to expect alas I did find it difficult to extract the faint dust which was barely above the background ADU count - very weak signal. This is the first time I experimented with PixInsight in the work flow - DBE and StarAlign with Frame Adaptation. Not sure if I would say this made the work flow any easier. Frame adaptation still has limitations in my view. Manually performing the panel matching still provided a superior result even if it took me three times as long. I've got the time and patience if the result is one of quality. DBE took some getting use to. Completely ripped the guts out of galactic cirrus the first few parses as its signal is so faint, it mistook it as a background gradient. Really need to selectively manage the data points. No doubt I'll look to incorporate further routines into the work flow and experiment accordingly but I don't see it replacing CCDStack and Photoshop any time soon, that's for sure. Shadow/Highlights is just a real gem for this type of work. The data has been pushed rather hard (actually appears sharpened, but its not) to bring out the structure and as such some noise is present in the extremes. Such as life! The signal is faint and tedious to work with. I'm not going to chase it down to get a plastic looking image. Anyway, enough mosaics for a while (I think). A couple of single frame images to come when I get around to them.
Thanks for looking. Hope you enjoy it. All comments welcome. :)
PS. I've also added an annotated version of the IC4628 image, it can be viewed from the image page (http://cosmicphotos.com/gallery/image.php?fld_image_id=230&fld_album_id=9).
Stevec35
11-08-2011, 10:17 PM
Very nicely done Jase. I would be more than happy with that.
Cheers
Steve
Hagar
11-08-2011, 10:25 PM
Now this is something different Jase. Very very nice crisp image.
Craig_L
11-08-2011, 10:27 PM
Haven't seen dust quite like this - so wide. Love that charcoal colour and the composition.
strongmanmike
11-08-2011, 10:36 PM
Funny, I looked at the image first (naughty I know) before reading your blurb and my first impression was ah huh! "the shadow highlights tool" this filter gives a very characteristic look to an image when used anywhere near strongly. I have never really found where the right balance is but I try not to push it to a point where I can see that shadow highlights was used but that's just me (hey I try for blue backgrounds on purpose too...so go figure :lol:).
That said, very interesting and expansive field of a rarely imaged area, very nice work on some very faint stuff...I enjoyed the view of this outer suburb of Sarah's Nebula :thumbsup:.
Mike
Ross G
11-08-2011, 10:36 PM
Hi Jase,
Great colours and detail.
An excellent photo.
Thanks.
Ross.
Thanks Steve! Not an easy target, but whats life without challenges. Please you like it.
Cheers Doug. Not imaged often so it is different, that's for sure. Not much going on the field in the way of deep sky objects though. A few galaxies perhaps, but not much else. Thanks again.
Indeed the dust is quite extensive, Craig. I probably should have pushed it harder, but that's as much it the data would take. 900s luminance subs typically pick up significant signal at F/5, not so with this target however. Thanks again!
Thanks Mike! Interesting you picked out the shadow/highlights tool. Most of the main structure came out through basic stretches with curves followed by a few small S curves for minor contrast enhancement. Shadow/highlights was only used with an Amount of 5% and a Tonal Width of 15%. Hardly over doing it! Personally, I think it could use more. I would normally perform two or three layers masked of different strengths and blend them in, but it wasn't warranted for this image. The stretches previously took the data close to its limit. Perhaps an area for you to try out under dark skies at F/3.8. You'd probably nail it in 300s subs if the sky is dark enough. Forget about it under light polluted skies. You'll struggle to pick out the signal from the noise of light pollution. Thanks again for your feedback. Appreciated.
Cheers Ross. Pleased you liked it. The subtle colour differences in the dust are quite fascinating.
atalas
11-08-2011, 11:15 PM
Fantastic work Jase! three hours a panel really isn't much time on such faint structures.....showing your skill here mate.....The Southern Dust Buster!
Paul Haese
11-08-2011, 11:20 PM
It looks to be a tough gig Jase. I will have to put this on my list of dust to image. So many really cool spots to image. I too find the shadows and highlights tool to be great but it must only be used in very small amounts.
BTW, nice work Jase.
jjjnettie
11-08-2011, 11:48 PM
Well I'll be!!! Who would have thought THAT was there. Nice work Jase. :D
gregbradley
11-08-2011, 11:58 PM
A great find Jase. It goes to show to some degree that space is still largely unexplored.
Blending of panels is not as good as you usually get it. Gradients?
PixInsight has a new HDR gradient tool which is supposed to make blending seamless. I have yet to learn it fully but it sounds promising.
Greg.
I'm always amazed with what you pull in Jase.
Love it !
Fantastic dust structure there.
Octane
12-08-2011, 12:21 AM
Jase,
Another work of art by the master.
Just look at those star colours. :eyepop:
Love your work.
H
Cheers Louie! Yes, I would have like to of obtained more data however the weather hasn't been very forgiving down south. I threw around four hours of data out due to passing clouds. What remained was of solid quality so decided to try process it. Appreciate the comments!
Thanks Paul. Yes, rather tricky to process. You're right, there are features in the dust that scream for longer focal length work. It would make for an excellent image. Even a longer focal length mosaic if you're up to it. I'm yet to fully appreciate the shadow/highlights tool to be honest. I only know the basics of what it does having read a few articles on the algorithm it uses. Very powerful, but as you say, it needs to be used sparingly. Thanks again!
Thanks JJJ! Uncharted territory!
Cheers Greg. The area is known, but not often imaged. Its quite difficult to image due to image rotation around the pole making mosaic panel overlap critical. The DBE tool in PixInsight cleaned very minor gradients. Being a dark sky site, they weren't caused by light pollution. I don't see many issues with the panel matching. If you use the equalise tool, it's still pretty hard to see the blending defects. I'll take a closer look though. I'm going to spend more time with PixInsight, it does have some unique tools but the challenge is understanding what they actually do to the data. I'll take a look at the HDR gradient tool - sounds good, thanks for the heads up.
Hey RB! Great to hear from you! Thanks for your comment. Appreciated!
Cheers H. The usual heavily stretched RGB layered as softlight works wonders on star colours. Pleased you liked it mate!
John Hothersall
12-08-2011, 01:31 AM
That is a wonderful vista of dust and so detailed, there seems to be dust almost everywhere but it is so faint lost in the ADU as you say. Processing skills seem to make the difference.
John.
iceman
12-08-2011, 04:45 AM
Wow, I've not seen that before. Beautiful image Jase. thanks for the view.
SkyViking
12-08-2011, 06:07 AM
Simply amazing Jase. Those delicate wisps of smoke look so intriguing. And the processing is superb, very inspiring stuff.
Thanks for sharing your image.
Thanks John! I did leave the black point quite low to express the super faint structure. Raising the black point would have probably cleaned up noise but at some expense. Appreciate the feedback!
Cheers Mike! I'm surprised people don't image this area much. The further south you are the better it gets. I should add from my southern location this scene crosses the meridian at an altitude of 52 degrees. Still quite low to get good detail. I had to compensate for atmospheric extinction in the blue channel quite heavily. Thanks again!
Thanks Rolf! Am pleased you enjoyed it and found it of inspiration.
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Thanks again all! :)
JohnG
12-08-2011, 09:17 AM
Hi Jase
A lovely area of sky, one never knows what is hiding up there.
Don't get on here often these days, nice to see your work again.
Cheers
Thanks John! I appreciate you dropping in to take a look and comment. Appreciated. Hope to see you around again soon.
As a late comer, I too have never seen that before, but you have certainly captured that beautifully Jase, you don't do it often, but when you do it is awesome stuff.
Leon
Bassnut
12-08-2011, 12:59 PM
Excellent, unusuall. Nice change from the top 10.
Never too late Leon! Quality over quantity. As I've said before, if I can produce a couple of quality images a year then I'm satisfied. Its easy to fall into the trap of object fever where you shoot multiple targets a night. I'm happy to sit on a target for a month or two to produce something that works for me. Each to their own. Thanks again mate, I'm pleased you liked it.
Cheers Fred. Agree, its always refreshing to see something different. It becomes increasingly hard to rejuvenate the top 10, without major ingenuity. Thanks for checking it out.
Original, technically demanding, and beautiful.
Jase is BACK :)
p.s. I reckon ABE is under-rated in PI - DBE can require quite a bit of experimentation to get the right samples in place, but ABE can often give better results out of the box. Rogelio confirmed he will often do lots of trial runs with DBE before leaving it be.....
Dennis
13-08-2011, 07:25 AM
Oh my goodness, another stunning piece of astronomy art as we have come to expect from you Jase. As always, thank you for the rich commentary, which provides much insight into the selection and processing of these fabulous Jase masterpieces – you do it so very well.:thumbsup:
Now I just have to go and get meself a larger monitor!:)
Cheers
Dennis
multiweb
13-08-2011, 08:53 AM
Very interesting object out of the beaten track and very well processed too. Although it sounds like it is extremely faint the field and stellar profile look very natural. Nicely done indeed. :thumbsup:
Lester
13-08-2011, 10:22 AM
Going where few have gone before, Thanks for the wonderful view Jase. All the best.
midnight
14-08-2011, 08:07 PM
Fantastic Jase! Certainly a very interesting image and your processing balances deserve high credit. Thanks for sharing with us.
Darrin...
desler
14-08-2011, 08:23 PM
Hard to describe, how I feel about this! Amazing capture, masterful processing. Just hard to imagine it's actually up there. Always good to end a day with the thought that you've seen something that you've never seen before. Thanks jase.
Darren
LucasB
14-08-2011, 10:16 PM
Hi Jase,
This is simply breath taking!! Really inspires me to refine my technique to try and achieve a result like this.
Awesome stuff :thumbsup::thumbsup:
Lucas
dugnsuz
15-08-2011, 09:13 AM
Dark and foreboding - beautifully done.
Doug
Thanks Rob! Technically demanding it, but perhaps only because its so low in the sky. Some field rotation was present but nothing that couldn't be dealt with. Am still learning the ropes with PixInsight. I did try ABE, but it struggled to detect the differences in the background dust versus minor gradients. DBE is without doubt a fine tool but I can get similar results with PS GradientXterminator. The trick with the latter however is to ensure star and extended object selection and feathering is well defined otherwise its a mess. There is a good write up on the differences between ABE and DBE on the PI forum (http://pixinsight.com/forum/index.php?topic=108.0). Thanks again!
Cheers Dennis. I strive to show something different as it easy to fall into the trap of regular objects. As Fred politely put it - the top 10. Your philosphy is similar in that you image super dim clusters for example that are not regularly seen. It adds an extra dimension. Thinking outside the square is bound to drive different and interesting results. I do apologise for uploading such large images, but its really the only way to view mosaics. Not a fan of zoomify so will just stick with providing alternate resolutions. One day, monitors will catch up but its difficult with today's megapixel sensors. Really appreciate the feedback.
Thanks Marc. I did pay attention to the stars. I work on the principles for stellar profiles as I documented here (http://www.iceinspace.com.au/forum/showpost.php?p=666789&postcount=40). Stars can either make or break an image. If they are stretched so that they're all white, they can't be coloured given the RGB additive colour space. Thanks for taking the time to check it out.
Thanks Lester. Pleased you enjoyed it.
Cheers Darrin! The dust is certainly eye catching. There also appears to be a small reflection nebula present in the field. Thanks for the kind words on processing and making comment on the image.
Thanks Darren. Yes, there is much around our south celestial pole. I've got a few other projects planned in the area when the season is prime for the targets. It's certainly an area that deserves more attention. Thanks again for the feedback. I'm pleased you enjoyed it.
Cheers Lucas. The further south you are the more well placed imaging around the pole becomes. I don't normally start imaging until an object hits 40-50 degrees in altitude and that's only through a red filter. The thought of imaging through green, blue and clear filters while the target was so low worried me little. Unfortunately, it wasn't going to get any higher so had no choice. My skies are probably the darkest to the south and east so that would have helped. Am pleased it has provided inspiration. Nothing ventured, nothing gained when it comes to imaging. Thanks again.
Thanks Doug. Does have a sinister look about it. Thanks for checking it out!
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All, thanks again for your support and feedback. :D
Peter Ward
15-08-2011, 10:44 PM
"FM.....no static at all" (If you are not a Steely Dan fan this will make no sense at all :) )
Missed this one. Clearly another cool wall candidate.
Jaysus H... has it been clear in VIC???:P
...and as usual , nice one! :thumbsup:
Thanks Peter. Clear in Vic? Depends on who you ask. I don't wait up to check. Isn't that what cloud sensors are for. Thanks for checking the image out.
Phil Hart
16-08-2011, 09:39 PM
cool jase.. very dark stuff. glad to see you got to the end of this project. 12 hours exposure, 120 hours processing perhaps? and sounds like you've saved me the hassle of learning PI and i'll stick with PS!
inspiring stuff.. you've got a smoothly functioning system producing top notch work. :thumbsup:
phil
A wonderful image Jase, this is one dust cloud that I have not seen before. A very intricate and fascinating object I found myself being drawn into it.
Thanks for a glimpse at what is probably a rarely imaged object.
Cheers Phil. Yes, I recall speaking to you about it at AAIC - the whole pole rotation discussion is a challenge. Perhaps a Takometer/PIR with calculated PA variance would work, similar to what RBA used when imaging around the northern pole. Indeed, several hours spent processing this one - its a labour of love though. PI has some cool features. It doesn't do it all, nothing does. Its a matter of determining what works best for you and leverage the features you like to make the most of the data. Worth having a look. Thanks again!
Thanks Ric! I'm not going to turn into a dust aficionado, I'll leave that for others more qualified. I do however like to pick out interesting features such as the uncatalogued little reflection neb. Pretty cool. I'm pleased you enjoyed it. Thanks for checking it out.
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Thanks again all. :)
TrevorW
19-08-2011, 09:46 PM
Not seen this area imaged for gas clouds b4 although the colour seems a tad grey how indicative is this of the true colour
do you have other examples of this as a comparison
likewise nice work as usual
Thanks Trevor! Given this is a lesser known target, you wont find many comparative images but there is a few out there online. Its close to G2V but extinction factors could potentially be improved if I were super pedantic about it. Making the dust a deeper brown hue that we are familiar with is not difficult, but that's not how I wished to portray this scene. 'Pretty picture' imaging provides freedom of expression and that's precisely what I've done here. Perhaps give the target a go yourself. Will certainly test your gear. Thanks for checking it out - appreciated.
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