Small Magellanic Cloud @ 200mm f4

[dugnsuz]

Hello all...

Tried a mega-session on the SMC last night, 30 x 10min exps, no in camera noise reduction - I hoped the shear numbers of subs would smooth out any Signal to Noise problems!:rolleyes:

On final inspection the image suffered from soft focus and light pollution.
Think I'm heading in the right direction hopefully, but I don't think this is one of my best!!

Canon 40D (modded)
Canon 70-200mm f4L lens, 200mm @ f4
Skywatcher Synscan EQ5 mount
Autoguided with PHD

30 x 600sec exposures, iso1600
Stacked in Images Plus - tried "Exclude Average" this time, software deals with RGB data separately...worked out better than Average.:shrug:
Tweaked in PS.

Higher Res...
http://s327.photobucket.com/albums/k461/doug-robertson/?action=view&current=SMC-HI.jpg

Cheers
Doug

[leon]

Hey Doug, nice mate, wow that is a marathon run, I reckon it has come out very well indeed.

You mentioned a little soft in focus, well that could be possible, but I reckon it is a fine job.

keep at it mate, and keep em coming, wondering when you were going to post this, after I listed you as missing last night. :lol:

Leon :thumbsup:

[dugnsuz]

Cheers leon - and yeah I think focus is off.
Re the lack of ICNR - I found this an interesting experiment with the 40D as the background came out very smooth but the galactic detail was noisy as hell and a bugger to process:shrug: Why would the background be smooth or am I missing some fundamental law or summit!?:lol:

ps.. I also hate that burnt out glob bottom left!!!:mad2:

[leon]

Yea I know what you mean about that glob Doug, but you were pumping it at 1600 ISO, gee mate I don't go much past 400, but that is just me, I think your skies might be a bit darker than mine.

I know INCN is a bugger at times and doubles your time but it is really worth the effort, have you tried it over two nights and then combine both nights.

IMHO, maybe the background is smoother because there is less light to pick up, less than the actual object, can't really help much with that one, I'm not that experienced :shrug:

Leon :thumbsup:

[AlexN]

It does seem that the mass of exposure has kept the background noise well at bay... :) I know its a horrible idea, but how about shooting the same again, 30x10min @ ISO800 then layering in maybe 10x2min shots to normalize the glob.... It is a hell of a lot of work though, and to my eyes this has come up trumps as is! :D

[iceman]

Beautiful, Doug! I like it a lot. Nice background!

[gregbradley]

Great shot Doug.

If you want to handle that light pollution gradient, Gradient Xterminator will do an excellent job. There is a free trial.

Also it is easier to take some darks and flats and use them in Images Plus than using the noise reduction system of the camera.

Greg.

[Garyh]

Nice Doug! nice color balance and I find it a very pleasing image to look at!
That`s what its about!
cheers Gary

[RB]

I agree with Gary, Greg and Mike, it's a very pleasing image Doug.
Histogram looks fine with plenty of data.

Applying some flats will help this image and allow you better control I believe.
Did you apply any darks?

[dugnsuz]

Cheers Andrew and Gary,
No darks were used on this one Andrew.
:thumbsup:

[Craig_L]

Lovely colours Doug. Keep them coming.

[multiweb]

Just saw that one now. That's awesome Doug. Colours are great :thumbsup:

[peeb61]

Great image Doug,
I just love wide fields. Very crisp colours and the focus looks good.
Paul

[Bloodbean]

Hi Doug,

Absolutely love the result you've got there. Is the 70-200mm lens the IS version? That lens looks great wide open, most impressive.

Have you considered stopping the lens down to f/5.6 to get a wee bit more sharpness? Again, the image looks brilliant well done! ;)

Troy

[Tilt]

Great image doug, the Canon 70-200 strikes again!

Michael

[dugnsuz]

Craig, Marc and Paul - Cheers:)

Troy... the lens is the Non IS version, I've tried stopping it down on a few of my images. I find it pretty sharp at f4 though - I think in this case the focus may be slightly off. Examination of the actual size pixels in PS confirmed this.
Thanks for the comments:thumbsup:

[AlexN]

i've found the 70-200 f/4l to be as sharp wide open as it is stopped down.. Some times f/4 out performs f/5.6.

[RB]

Yep I agree Doug, I noticed it's slightly off focus, but as you say you're very safe using this superb lens wide open, especially for astro.

:thumbsup:

[dugnsuz]

:):thumbsup:

[winensky]

Lovely wide field, great colour. Couldnt pick the focus problem but my eyes are getting worse by the month. At ISO1800 and those exposure times the nebs are comming out to play.I don't knoww if you can selectively unsharp and layer the glob but a great job all together.

[dugnsuz]

Thanks Matt.
One day I'll get my act together and really plan one of these imaging sessions!! Flats, Darks, various exposure times etc etc.
:rolleyes:

[Jen]

Nice pic Doug :thumbsup::thumbsup:

[dugnsuz]

Cheers Jen - thanks for having a look:)
Doug:thumbsup:

[TrevorW]

Nice Dougie but was is the opitmal ISO setting for images i've tried 400 and 800 without that much difference. Is it better to take more shorter timed exposures or less longer ones. Personally I would think to err on the side of more shorter exposures reducing the effects of rotaional distortion, tracking errors and noise pollution etc:shrug:

[AlexN]

in ideal conditions you would go for longer exposures.. Rotation and tracking shouldn't be a problem if you're aligned properly..

[dugnsuz]

No Trev,
Live on the edge mate!!!

I'm just trying to push the little envelope I find myself in!

Sometimes it pays off - in this case I'm not convinced, I sacrificed NR to get the large numbers of exposures in the given time.Also no LP filter didn't help.

Re your question - I've always looked at it thusly...
I can take a number of 5min and 10min subs. The 10min sub will record fainter photons than the 5min sub. I can stack as many of those 5min subs as I like - the fainter photons recorded in my 10min subs will never be there in that 5min stack. So my goal is to stack as many 10min exps as possible:) Genius!!:lol::P

All the best
Doug

[iceman]

Are you calibrating, Doug? Flats and darks?

It's a nice image! Well done.

[dugnsuz]

Cheers Mike,
Basically a rough - no ICNR, 10 min subs, iso1600 stack...so no calibration on this image at all!

Just a bit of fun really!!:lol:

Doug:thumbsup:

[leon]

Fun It maybe Doug, but you are getting some nice results, and you are having fun, arn't ya, :shrug: so what else is there. :whistle:

Leon :thumbsup::thumbsup:

[dugnsuz]

Nice summing up leon!!:)