M8 in Ha STL+FSQ

[montewilson]

Hi Guys - Here is an M8 and neighbours I took last weekend at ASNSW site near Ilford.

It is 7 x 10 mins with the STL-11000m and an FSQ-106 and a 5nm Ha filter.

It will be part of an HALRGB when the weather permits.

Enjoy.

Regards

Monte

[Zuts]

Hi Monte,

Very good work and nicely framed. This will be a very long project if you rely on Ilford new moon weekends :)

Paul

[Garyh]

Nice Monte! I like composition!
Must keep us folks on IIS updated as this progresses!
cheers Gary

[jase]

Indeed as the others have said, the composition is great Monte. I'm not certain what has happened to your highlights however. The image tonal range looks suppressed. If you drop the white point down to ~202 and raise the black point to ~14 using levels, you'll see what I mean. The histogram has too much space, thus you are not taking advantage of the available range. Just blink the modification by toggling the preview check box. If you think you're clipping data, hold down the alt key as you move the black and/or white point sliders. This will provide a direct indication of the data you've clipped (if any). What the stars and the hour glass in the process. I'll be interested to see how you manage the Ha data integration with RGB. This is always good fun.

Look forward to seeing more...has been sometime since we've seen your work. Don't leave it for too long.:)

[montewilson]

Thanks for the comments guys. I owe a debt to Mike Sidonio who commented on my image even though I didn't on his exceptional 5128 shot. I had planned to do so and got distracted and then it became an old thread. It is the best 5128 I have ever seen. Those faint arms are really interesting.

Anyway here is a version as suggested by Jase who as always has gems falling from his keyboard.

[montewilson]

I have a question about the noise in this image. I have done a median combine, and a remove hot cold pixels at the subs level. It seems so noisy/grainy.

Any thoughts?

[Bassnut]

Smooth and detailed Monte, nice one.

The noise is because your taking only 10min 5nm Ha subs on a ST11k (30% QE?). I think 20min or more would be the go. In fact your result is pretty good for only 7 off 10min. I bet the ADUs on the nebula were less than 1000 on the subs.

[skeltz]

Very nice monte,you got some good detail there...but yes try longer subs...push the stlk,go for it
cheers rob

[AlexN]

Awesome image... I am going to need a Ha Filter :D

a note on noise... Download a program called NoisewareCE (google it..) It works wonders on cleaning up images... Free version is good, the cheap full version is better... :)

Other than that, My congratulations on a fantastic image... you've definitely got alot of nebulosity in there.

[marc4darkskies]

Hey Monte! Nice one - it'll be sweet with some RGB! :thumbsup: Yep, with a 5nm Ha, you should definitely go with 20 min subs next time (at least). I'm doing 30 with my 10nm these days - gives me more S/N than I can poke a stick at.

Cheers, Marcus

[strongmanmike]

Well thanks Monte :thumbsup:

Funnily enough the new director of Mt Stromlo and Siding Spring Observatories, Prof Harvey Butcher, said the same thing about my Cen A image at the David Malin Awards, I was most chuffed :D

I must say that I too like your composition on this Lagoon Trifid shot and your new vesrion looks even better. As Jase said, it will be interesting to see how you go with the RGB combine, good luck cause if you get it right you have here a potential Malin award candidate ;)

Mike

[montewilson]

Is there a link for the awards? I wanna see !!!

[strongmanmike]

Gee wizz, where you been at man? :eyepop:

Here is the CWAS results page:

http://www.parkes.atnf.csiro.au/news_events/astrofest/awards/

This from my web site (a bit self focused of course, sorry) for some other photos :P

http://www.pbase.com/strongmanmike2002/david_malin_awards_2008

Mike

[Dr Nick]

Nice shot, love the higher contrast version.

If only my telescope would allow such a wide-field to image with... ;)

[gregbradley]

Very nice shot. But hey its upside down! hehe

Yes the noise is from the short subs and total exposure time and in fact you did well to show NGC6559 so well with 70 minutes. Thanks for the FSQs F5 and the dark skies eh?

30 minutes is good in theory but harder in practice - tracking errors, polar alignment errors start to show and of course it makes you more vulnerable to cloud interruptions. So if you have good polar alignment and good tracking and no clouds then go for it.

Sometimes imaging parameters are something decided on the night based on the conditions you have. Especially when you travel to your site.

Its no good doing 20 minutes subs with cloud coming over every now and then for example. You'll end up with nothing.

Your second version is better except for the core of M8. You had better detail right to the core. The data is there.

So,

Lassoo the core and run either curves on it or shadows/highlights until the core detail is returned. You'll have to feather it 25 pixels and if you hit control H after you lassoo an area or select an area the lines that show the selection are hidden and it is easier to see the effect your processing is having.

Greg.

[montewilson]

Hi Greg - I just tried that and it makes a big difference. I will post an updated image soon.

[montewilson]

Thanks Greg for the suggestions on PS. Here an updated version. I have used the lasso tool on some parts (multiple concentric passes on the main nebula) and a light sharpen too.

I think it looks better but I also feel it looks a bit non credible.

Wa da ya reckon??

[iceman]

Looks really nice to me, Monte! Excellent wide field.

[montewilson]

Hey early bird ! I guess its just that I am used to the hot centre of the nebula.

[iceman]

Do you have a higher-res version we can look at?

[gregbradley]

Hi Monte,

Hard to say. It does stand out a little but not much, it is brighter than everything else like it actually is.

That's why hitting control H after you have made a selection is a good tool as then the selection lines don't distract you from seeing the effects your processing has on the selected areas and you can make it match its surrounding area more easily.

Greg.