NGC 6231 in Scorpius

[Octane]

Hi all,

Read and view here (http://members.optusnet.com.au/mrozycka/Magellan_Observatory/Magellan_Observatory_20070622_NGC_6 231.html).

Warning: file is approximately 1.17 MB in size.

As always, comments and critique welcome.

Regards,
Humayun

[ballaratdragons]

Well Humayun,

Nothing to critique! It is a great image. Stars are nice and round right out into the corners of the image and the Star colours seem correct.

And it's nicely composed :thumbsup: Well done, I like it very much. :)

[ballaratdragons]

I love finding those Blood-Red stars! You have quite a few in your image. Here are just a few in one corner.

[iceman]

That's a lovely open cluster, H. Very well done.

[Garyh]

I agree with everyone, nice colors and a fine image of this cluster...keepem coming!!!
cheers

[jase]

Well composed Humayun. Colours are looking good and the stars within the open cluster resolve well. Look forward to seeing more. :)

[erick]

Thanks Humayun. Lovely! I'm printing a copy for Leo76. This is the first open cluster she "discovered" with binoculars so it has a special place for her. Eric

[Octane]

Ken,

You're a keen-eyed observer! I noticed the red stars whilst processing, but, didn't realise how much different they are to the rest of the field. Well done on spotting them! :)

Cheers, mate!





Mike,

Cheers. :)



Gary,

Thanks! More to come soon!



Jase,

Aww, no in-depth critique this time? :P Just kidding! Thank you. :)



Eric,

Go for it, mate! It definitely is a beautiful cluster. I think it's one of my favourites, along with M6, M7 and the Jewel Box.

It's actually a tie between NGC 6231 and M6. Both gorgeous.

Cheers!



Regards,
Humayun

[jase]

Nah, thought I'd let you off the hook this time.:P;). Seriously it is a great image. Though I would like to make one comment. This image is a good example of the PS equalize function I mentioned on your M8 post. Try it on this image and let me know what you see. You'll find you have a band of red that evenly runs across the bottom of your image. I'm not entirely sure whats the cause of this as I'm not familiar with your set up. This simply results in your background not being neutral as you'd expect. There are also large patches up the left corner of the frame, but this could purely be the nebulosity from IC4628 as its quite a large emission nebula. The red band across the bottom looks too even/straight to be natural. I'm going to be honest, sometimes I just ignore the background colour shifts. Its depends on how it affects the final image presentation. If you're keen - chase them with selection tools and curves. In this particular case, I'd probably wouldn't address it, but with wide field images it can have a larger impact. Great image none the less.:thumbsup:

[Ric]

A wonderful image Humayun, a lovely well defined cluster.

Great effort

[Dr Nick]

Nice pic! ;)

[Octane]

Jase,

:P

As soon as I get a spare chance (and get back to Canberra) I will do as you've recommended and have a look at what's going on. I have noticed the band of red in the bottom before, and I'm just wondering whether it is bodgy dark frame subtraction (I doubt it, though, IRIS is awesome) or a result of me pushing the curves too much.

Thanks, once again. Your advice is most appreciated.



Ric,

Cheers, mate. :)



Nick,

Thanks, once again. :)



Regards,
Humayun

[avandonk]

Hamayun I have also noticed this and have tracked it down to the cameras mirror edge attenuating the incoming light. If you have a look at the two images below they are flats taken with the 5DH with the contrast maximised to better show the effect.
One is with the Canon 300MM F2.8L and the other the 100ED. This can lead to an apparent colour gradient along the bottom of the image if the flat is not made neutral in colour by adjusting luminance to 0.33 for each colour and gamma to 1.0.

The bottom of the image is in reality the top of the camera where the mirror is while an exposure is in progress.


Bert

[jase]

Well spotted Bert. That would appear to be the culprit.

[ballaratdragons]

Sorry,

I just couldn't refuse :whistle:

[h0ughy]

fantastic RESULT AND NICE DIAGNOSIS GUYS