NGC4038 Antennae galaxy-close up

[Bassnut]

Hi guys

The infamous colliding galaxies (http://sites.google.com/site/fredsastro/)in bog standard LRGB, none of your weird NB here :D.

Far too many exposures, but you have to to beat sky glow :P.

Lum 10hrs bin1:RGB 6hrs each bin2, all 10 min subs. I couldnt image anything else at the time, so why not, and it allowed decon on the RGB subs, which is rare.

AO was doing its vibrating thing at a lazy 1hz only.

Many, many layer masks used in PS to tame noise.

Image is fairly croped.
Im fully expecting a sid on this, depending on feedback, so cane me, Im ready :D :poke::scared3:

[DavidU]

Amazing detail ! Nebulosity, dust lanes,I hate you.:D

[Peter Ward]

Fred! Stratospheric deep sky resolution that needs a step back. Throw away the eggy star data..sometimes less is more. Great colour :thumbsup:

[h0ughy]

fari dinkum - stars and details in normality - fred you must be trippin ;)

nice result i can see it twisting and writhing like its alive

[Hagar]

Lovely detail Fred but it does look a little like a red tint to the top area of the image fading out as you get to the galaxy itself but is evident in the faint stuff of the arms at the top.

Detail and vibrancy is magnificent but so many hours of data. A lot to play with but worth grading a bit harder.

Well done. Great patience for this long an exposure.

[marc4darkskies]

Very, very impressive Fred!! :thumbsup: :thumbsup: What detail!! And thanks for the stars and "real" colour!! :)

Maybe your noise reduction efforts are a little too obvious in places and the stars in the antenae are a little soft, but that's an amazing shot!!

Cheers, Marcus

[strongmanmike]

I like the glowing look the HII and bright star regions have and the detail is great for sure but I agree with Marcus on the smoothing you look to have lost some faint vein like dust lanes in the smoothing of the billowing areas plus to me it has a noticable purple/mouve colouring that dosen't look natural to me..? Maybe all those hours processing the NB planetary neb images has clouded your colour balance sense just a little ;)

Still, another impactful in your facederhaven image!

MIke

[Ric]

A wonderful image Fred, the detail in the galaxies is pretty darn amazing.

Cheers

[multiweb]

Wow! Great details and colors in the cores. Amazing shot. :thumbsup:

[gregbradley]

Great image Fred. One of the best of this object I have seen.
It looks very bright and solid with details instead of the usual blurry indistinct object. Perhaps the tail areas are a tad oversmoothed and the blues have a bit of magenta in them that may be colour balance (playing with selective colour/blues may get a better shade of blue). Then again there may be a lot of Ha at the top of those 2 galaxies, who knows.

Greg.

[RB]

Ditto to what Marc said.
Well done Fred !

:)

[Lester]

Outstanding image Fred, thanks for the wonderful view. All the best.

[renormalised]

Great shot, Fred!!!. Looks almost 3D!!!:)

[Bassnut]

Thanks for the compliments guys, and the feedback.

Peter. The stars were seperate short exposures, but I still have trouble getting good colour on them, and yes, I did clip them a bit, ill fix it (or did you mean droping them altogether?).

Dave. "normality", in a slightly wonky sort of way :P.

Doug, OK, ill fix that gradient.

Marcus/Mike. The noise reduction is severe in places, but the dust halo is in fact very fuzzy anyway, and very large, I actually decurved and reduced it a bit, due to noise . The stars in the middle are oddly smeared, ive seen that in nearly all galaxy pics, its almost like its something else than stars, nebs perhaps?. The tinge is not obvious on my monitor, ive never set it up tho,mmm might have to do that.

The faint veins in the dust lane were there, but extremely noisy, ill have another go at that, but it gets to boarderline hand painting then :rolleyes:.

Greg. The tails are extremely dim, you sometimes dont see them at all in pics, and noisy, hence the smoothing, again, ill have another go.

This is the kinda feedback I needed guys, especially the magenta/red tinge/gradient I dont see on my monitor, noise and edgy stars.

Thanks again :thumbsup:

[bert]

I agree with Mr 'Maranello' Ward. Ditch the stars, I think there may be a tutorial somewhere here on how to do it.....:P

Brett

[spearo]

Great shot
frank

[telecasterguru]

Fred,

The image is fabulous but can I ask, if you did 28 hours of data, what about flats and darks and the likes?
Did you or didn't you and if you did how much and how were they processed?

Frank

[Bassnut]

Thanks Brett, Frank and Frank.

I think ill fix up the stars on this one, I already did exposures just for them.

Frank. I took the standard library of darks just for this object, because every time you change the rotator position, you need a new set. I never take darks for NB, I found they are just not needed. The background is always so dark, you dont get gradients either.

Darks are from a standard library I use for every pic, I updated every 6mths or so. Darks are always 10 off combined. 10 is about optimum for any exposure length IMO, the total light exposure time is irrelevant, regardless of the number of subs taken, as darks are applied to each sub.

I use CCD stack, but any astro app is much the same, you select the dark to suit the light exposure length and click calibrate, it then calibrates all the subs automatically (any selected number of subs you wish, its the same one operation), some apps select the right dark automatically too. Makeing master darks from 10 dark subs is something you do once when you take the darks, and is handled by astro apps automatically with a few clicks.

If your question really is are the darks/flats or procceedure different for very long total exposure times/large no of subs, no it isnt, its exactly the same, as its only each sub that counts for calibration.

[Moon]

Fred,

Wonderful shot - the hours have really paid off.

I found Mr. Antennae to be a bit too tricky... he's in my 'too hard' basket at the moment.

James

[telecasterguru]

Thanks Fred,

The question was about optimum use of darks/flats for any given processing.

Now that I have ccdstack v2 I think this should make calibration and processing easier.

Frank

[TrevorW]

Nice Fred

[Bassnut]

Thanks James and Trevor.

Frank. I dont change calibration methods other than no flats for NB.

Always apply darks to any sub, and flats to LRGB.

And BTW master flats made from 10 subs is also pretty standard.

Make sure you take darks at a bunch of common light exposure times, say 2,5,10...20mins? at bin 1 and 2, all at the same temp you take lights.

If you take very short flats with a bright scource, you dont need darks for them (very tedious), the noise for exposures of a few seconds is so low it doesnt matter.

CCD stack is the best IMO, but a bit manual. Its well worth reading up the instructions cover to cover. Once you know it, its easy to use.

[Paul Haese]

Nice process of what I found to be a hard target. Even with 9 hours of data I could have taken another 10 or more. Your rendering is better than mine and noise control is not bad either. Level of detail looks great too.

[Shiraz]

ditto other comments - that is a spectacular image.