A fairly deep NGC 6231

[Stevec35]

This image is centered on the bright open cluster NGC 6231 in Scorpius. I've been adding to it from time to time and last night managed to get 3 hours of Ha. I probably overdid the saturation again but I make no apologies for liking colorful images.

Cheers

Steve

http://members.pcug.org.au/~stevec/ngc6231_STL11K_FSQ106.htm

[Peter Ward]

This is pretty. H alpha, beta and dust in the mix.
Nice one. :thumbsup:

[Logieberra]

Nice one Steve, I'm glad that the clouds opened up for your new FSQ :)

[Ross G]

A very good photo Steve.

I really like the colours.

Ross.

[Joshua Bunn]

HI Steve,

This is very pretty with a variety of colours in the star fields and nebula. Nice. The sheer population and density of the field is very attractive also.

thanks
Josh

[Stevec35]

Thanks Josh. There's certainly a lot going on in that field. Maybe I'll do a mosaic.



Thanks Ross



Thanks Logan. It's not so new any more. Been more than 6 months now.



Thanks Peter

[madbadgalaxyman]

lovely image showing the cluster, and some of the associated OB association, and part of the giant arc of nebulosity on one side of the cluster.

I seem to recall that the cluster is one of the most prominent groups of (supergiant & superluminous) OB stars in local space.
I can't remember whether the supergiant arc of nebulosity is caused by the energy emitted from the cluster stars or by a supernova.

Here is a larger section of the supergiant arc or shell, from wikisky:

114261

[Stevec35]

[QUOTE=madbadgalaxyman;847097]lovely image showing the cluster, and some of the associated OB association, and part of the giant arc of nebulosity on one side of the cluster.

I seem to recall that the cluster is one of the most prominent groups of (supergiant & superluminous) OB stars in local space.
I can't remember whether the supergiant arc of nebulosity is caused by the energy emitted from the cluster stars or by a supernova.

Here is a larger section of the supergiant arc or shell, from wikisky:


Thanks Robert. I must check out Wikisky. The attachment is very nice.

[gregbradley]

Oh Steve that's an awesome image. I love it!

I imaged NGC6231 a while ago but I never got much exposure time but I was excited by how good the subs were. I had no idea there was all this Ha around it. Mine was a much smaller image scale.

Your image is inspiring.

Greg.

[Paul Haese]

Superb image Steve. Great colour, lots of objects (I particularly like the dark tower) and great composition. :thumbsup:

[Stevec35]

Thanks Paul. I've made further, hopefully non detrimental, changes to it so that the nebulosity is emphasized more than the stars.



Thanks Greg. I'm glad you liked it.

[madbadgalaxyman]

Your very fine image has got me curious about what is going on in this dynamic area of our Galaxy!

The supergiant shell nebula is likely to be called RCW 113 , also known as Gum 55, but I have to check this. I have reliable Idents for many of these nebulae, hidden somewhere in my tall piles of scientific papers....but I must dig for it!

The cluster itself forms the core of Scorpius OB1, which is an extended association of O and B stars. (= Sco OB1)

N6231 has been reported as having 9 stars of spectral type O, which means that the cluster is the source an enormous amount of ionizing Ultraviolet Light output into the surrounding interstellar medium. Wouldn't surprise me if the cluster itself was the energy source for the supergiant shell.

Johannes Schedler has done an extremely wide field shot of this region, see:

http://panther-observatory.com (http://panther-observatory.com/)

(It is necessary to scroll a long way down his page of thumbnails)

[madbadgalaxyman]

An interactive (with zoom and pan) "virtual observatory" type interface that allows you to move over the face of the Milky Way, in H-alpha (and other wavelengths) is the Milky Way Explorer:

http://galaxymap.org/mwe/mwe.php

If you select the option called "SuperCOSMOS Hydrogen Alpha", this enables you to view and move over much of the southen Milky Way as seen in Halpha.

[Stevec35]

Thanks for the info Robert. Yes you do get the impression looking at the image that NGC 6231 is the source of practically everything that's going on.

Cheers

Steve

[madbadgalaxyman]

Agreed, Steve.
And what a magnificent and complex region it is.
This area is grand enough to get my mind & eyes off those external galaxies, for a while.

[strongmanmike]

Hey that's a beauty Steve, such a diverse area - great stuff

Mike

[Stevec35]

Thanks Mike. It certainly turned out a more interesting image than I thought it was going to be.

[TheDecepticon]

Yes, very cool. Great visual cluster, too.:)

[Stevec35]

Thanks. It is a great cluster.

[multiweb]

Real nice close up Steve. :thumbsup: It's a great region in Ha. I shot that (https://skydrive.live.com/?cid=6930D3AD12D5044C&id=6930D3AD12D5044C%21863#cid=6930D 3AD12D5044C&id=6930D3AD12D5044C%21899)with the hyperstar a while ago no really knowing where I was and trying to find the prawn. :lol:

[marco]

Very Nice Steve, really looks the overal color rendition, well done!

Clear skies
Marco

[Stevec35]

Thanks Marco



Thanks Marc. I was going to include the prawn in this composition but decided to centre on NGC 6231

[madbadgalaxyman]

If you search in Google books , within the book "Sky Vistas: Astronomy for Binoculars and Richest-Field telescopes" by Crossen and Rhemann, you can find a couple of pages of detailed info about NGC 6231 and its associated broader concentration of stars known as Scorpius OB1.
I might abstract some of this info for IIS forum.

The total luminosity of NGC 6231 is comparable to that of Omega Centauri (!!), and the overall concentration of stars (cluster plus association) is a major tracer of the nearby spiral arm, that we see edge-on ; the arm runs from Sagittarius to Carina.
Oddly, this spiral arm is currently rather quiescent between Norma and Crux, with only a few major nebular complexes seen in this part of the Milky way, and these few nebulae are not very bright; there are not a lot of clusters of hot young stars that cause the interstellar medium to glow, in this part of the Milky Way.

[alpal]

It is a beautiful photo - well done.


As a minor point:
What about the blue halos around some stars?
Could that have been removed by better focusing of the blue filter?
I wouldn't expect halos from an FSQ using Astrodon filters.
Maybe the stars were just so bright that you were stuck with it?

[iceman]

I really like this Steve! One of your best I think.
No need to apologise for super saturated colours - I love it too :)

This is now IOTW (http://www.iceinspace.com.au).

[TheDecepticon]

Congrats on your IOTW. :thumbsup:

[strongmanmike]

I second that and poroxy for Marcus Davies too :D

Mike

[Logieberra]

Way to go Steve, representing the ol' ACT on IOTW!

[Stevec35]

Thanks Logan



Thanks Mike



Thanks Graham



Thanks Mike. Rob Gendler said he would turn the saturation down just a tad but it's all a matter of taste. It's funny that this image started out as a test as I'm still having some flex problems with the FSQ.



Thanks. I thought I checked focus for every colour. It's possible that the brightness of the stars did it. I did try and minimize the halos but the effect looked a bit unnatural. In any case I think the blue halos emphasize the fact that these are hot blue white stars.



You are certainly a mine of information Robert.

[marco]

Very nice Steve, by coincidence I have also almost completed the processing of an image I took of a small part of this complex, certainly it is a very interesting area not so often imaged by ameturs. Your shot render it at full glory ;)

Clear skies
Marco

[Leonardo70]

Congratulations Steve, this is a really great image.

All the best,
Leo

[Stevec35]

Thanks Leo



Thanks Marco. I think many amateurs are ignorant as to what's there. The whole area is full of Ha.

[Ric]

Congrats Steve for your "Image of the Week"

It's a great image of a fascinating area of the nightsky.

Cheers

[madbadgalaxyman]

Yeah, I can be a bit of a "know it all", but I do try not to rub it in, and hopefully my comments are relevant....

I have got very interested in this issue of why it is that NGC6231, which is at a (rather uncertain) distance of some 5000-6500 light years, and which is so remarkably luminous that it is a bright object in amateur telescopes despite its considerable distance, seems to be just about the only such "young & luminous, very OB-star rich" cluster in the Milky Way between Scorpius and Circinus. Of course, there must once have been a massive "Eta Carinae -like" nebula surrounding the cluster, which was energized by the stars of the cluster, but it would have been quickly dissipated by the energy output from the cluster stars.
The dark clouds that make up the "Emu" in this part of the Milky Way are giant clouds of molecular gas, with some dust admixed......so I do wonder if these dusty clouds are hiding any objects like NGC 6231?

I think I better move any further discussion of this object to the science forum!!

[Stevec35]

I enjoy your comments Robert so no need to move as far as I'm concerned



Thanks Ric

[LightningNZ]

Congrats on a beautiful image Steve. Definitely my favourite of all I've seen of this cluster.

Where do you do your imaging from? One day I'll have a car and will escape these Belconnen lights.

Cheers,
Cam

[madbadgalaxyman]

Mad Galaxy Man wrote:
" I have got very interested in this issue of why it is that NGC6231, which is at a (rather uncertain) distance of some 5000-6500 light years, and which is so remarkably luminous that it is a bright object in amateur telescopes despite its considerable distance, seems to be just about the only such "young & luminous, very OB-star rich" cluster in the Milky Way between Scorpius and Circinus."

I just blew $90 on a recent book, so as to better understand these issues regarding star formation regions, star clusters, and nebulae, in the southern Milky Way!!
The book is called "Handbook of Star Forming Regions : Volume II, The Southern Sky", edited by B. Reipurth(published in 2008)

This isn't going to be an easy read, as it is an 890 page professional monograph, but I just love digging up these kinds of details!
(For many years now, I have only studied galaxies external to the Milky Way, but I once did spend some years as an enthusiastic student of Milky Way structure.)

[Stevec35]

Thanks Cam. I just image from my backyard observatory in Theodore. Not perfect but the lights don't seem too bad.

[bloodhound31]

Always a fan of your work mate. I'm sure I will be studying your work again when I finish the obs and get back into it.

Lovely work.

Baz.

[marc4darkskies]

Another beauty Steve! :thumbsup:

Just a wee bit too saturated for my taste ... but I respect yours! :)

Cheers, Marcus

[Stevec35]

Thanks Marcus. Yes perhaps I'll tone it down a bit. Several people have said the same thing.

Cheers

Steve

[Stevec35]

Thanks Baz