Nebulae of the Octant

[jase (Jason)]

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
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 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.

[Stevec35 (Steve)]

Very nicely done Jase. I would be more than happy with that.

Cheers

Steve

[Hagar (Doug)]

Now this is something different Jase. Very very nice crisp image.

[Craig_L]

Haven't seen dust quite like this - so wide. Love that charcoal colour and the composition.

[strongmanmike (Michael)]

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 ).

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 .

Mike

[Ross G]

Hi Jase,


Great colours and detail.

An excellent photo.


Thanks.


Ross.

[jase (Jason)]

Originally Posted by Stevec35

Very nicely done Jase. I would be more than happy with that.

Cheers

Steve

Thanks Steve! Not an easy target, but whats life without challenges. Please you like it.

Originally Posted by Hagar

Now this is something different Jase. Very very nice crisp image.

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.

Originally Posted by Craig_L

Haven't seen dust quite like this - so wide. Love that charcoal colour and the composition.

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!

Originally Posted by strongmanmike

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 http://www.iceinspace.com.au/forum/....milies/lol.gif).

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 http://www.iceinspace.com.au/forum/....s/thumbsup.gif.

Mike

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.

Originally Posted by Ross G

Hi Jase,


Great colours and detail.

An excellent photo.


Thanks.


Ross.

Cheers Ross. Pleased you liked it. The subtle colour differences in the dust are quite fascinating.

[atalas]

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]

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 (Jeanette)]

Well I'll be!!! Who would have thought THAT was there. Nice work Jase.

[gregbradley]

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.

[RB (Andrew)]

I'm always amazed with what you pull in Jase.
Love it !
Fantastic dust structure there.

[Octane (Humayun)]

Jase,

Another work of art by the master.

Just look at those star colours.

Love your work.

H

[jase (Jason)]

Originally Posted by atalas

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!

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!

Originally Posted by Paul Haese

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.

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!

Originally Posted by jjjnettie

Well I'll be!!! Who would have thought THAT was there. Nice work Jase. http://www.iceinspace.com.au/forum/....es/happy04.gif

Thanks JJJ! Uncharted territory!

Originally Posted by gregbradley

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.

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.

Originally Posted by RB

I'm always amazed with what you pull in Jase.
Love it !
Fantastic dust structure there.

Hey RB! Great to hear from you! Thanks for your comment. Appreciated!

Originally Posted by Octane

Jase,

Another work of art by the master.

Just look at those star colours. http://www.iceinspace.com.au/forum/....eyepopping.gif

Love your work.

H

Cheers H. The usual heavily stretched RGB layered as softlight works wonders on star colours. Pleased you liked it mate!

[John Hothersall]

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 (Mike)]

Wow, I've not seen that before. Beautiful image Jase. thanks for the view.

[SkyViking (Rolf)]

Simply amazing Jase. Those delicate wisps of smoke look so intriguing. And the processing is superb, very inspiring stuff.
Thanks for sharing your image.

[jase (Jason)]

Originally Posted by John Hothersall

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.

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!

Originally Posted by iceman

Wow, I've not seen that before. Beautiful image Jase. thanks for the view.

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!

Originally Posted by SkyViking

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 Rolf! Am pleased you enjoyed it and found it of inspiration.

===
Thanks again all!

[JohnG (John)]

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

[jase (Jason)]

Thanks John! I appreciate you dropping in to take a look and comment. Appreciated. Hope to see you around again soon.