M83

[allan gould]

I think I finally have the spacing right with the f6.3 FR for the 10"SCT as I can now do full frame with the QHY8 chip and the stars in the corners were acceptable. I took 20x300 sec shots of M83 and combined in DSS and then processed in PS CS3. Im fairly happy with this preliminary shot with the QHY8 as its mainly for the colour as I'm going to get some luminance with the QSI583wsg and then put it all together.
I only did 5 min shots as I realise that I could have gone deeper (40 min subs) but the moon does tend to wash out the colour and details a bit and JetStar always use a flight path over my area.
Comments welcomed.

[dcalleja]

Nice image and framing

[peter_4059]

Excellent image Allan. The stars are looking good and there is a heap of detail in M83.

[gregbradley]

You got your reducer working nicely and I know that probably was quite a battle.

Nice and sharp and good detail. Object looks too magenta though and core isn't yellow enough.

Try selective colour in Photoshop and work on magenta and cyan and perhaps blues. It needs the magenta pulled back the cyan increased and the yellow of the blues increased.

I'd select the core (magic wand it then right click and grow several times) then increase yellow (hue saturation or colour balance or selective colour tool).

Greg.

[jjjnettie]

:D Nice one Allan.

[allan gould]

Thanks Dan, glad you liked it


Think I washed out the star colours with this shot. I think I'll have to learn how to remove the stars and process them separately before adding them back



Thanks jjjnettie - appreciate the coments and hope you are traveling well now.

[allan gould]

Greg
Thanks for the critical evaluation as I really appreciate your comments. I find the colour processing the hardest to balance and get right but it gives me a chance to do a Sidonio on it once I accumulate the extra data.
Allan

[[1ponders]]

Great detail Allan, I like it a lot. :thumbsup:

There does seem to still be some sort of gradient or poor flats reduction that has left a broad dark edge to the left side and a ring, that is slightly darker than the background, around the galaxy ( sort of like an inverse vignetting)

[strongmanmike]

Yes the basics are all there and a great galaxy to image Alan, I agree with Greg, try what he suggest and repost, see if you can deal with the right side gradient too, be interested to see the repro. :thumbsup:

Mike

[allan gould]

Paul
Your correct. There is a gradient that I noticed when I was setting the black and white points for the stacked image. I've had a go and can remove this gradient as it was caused by the moon coming up and of course the flats wouldn't have removed that light pollution. I've tried two methods so far and one worked well but I think I will try Iris and see if that is better. I think the ring around the galaxy was caused by isolating it to try and remove the gradient.


Mike
Will do a Sidonio on it - promise. And I've taken on board all you, Greg and Paul have noticed and will implement it when I get clear skies again.

[TrevorW]

Good effort Al, look to improve the colour of the background stars, IMO this will make an improvement that is noticeable across the whole FOV

[Hagar]

Very nice Allan, Looks like retirement is good. You seem to be imaging a lot more these days.
Need to try it myself.

[allan gould]

Ill have to go back and practice with PS to isolate the stars and do the colour of them as I feel Ive bleached them out far too much. This is something Ive not attempted to do before and would need a how-to from the net to do it. Any ideas?



Retirement is the best thing Ive done. Love every minute off it and Im so busy with all the little jobs etc.
Ive attached a Sidonio of the galaxy where I've redone the colour and removed the gradient from it. I found that after trying the background subtraction methods in PS, Annies actions etc etc that the best and most accurate was Iris. Long live Iris as its a great program that I feel I will have to get deeper into.

[TrevorW]

Generally the colour is thier what you can do is select the galaxy do and inverse select then increase saturation

Also Carboni Actions is worth the buy has a good star colour enhancement action as well as others

[gregbradley]

Nicer colour but you can see where you did a circular lasso around the galaxy.

Its better to use the magic wand tool and right click and select grow and do that several times until it is large enough to cover the whole
galaxy and then feather it by 50 pixels. You need to feather selections otherwise you end up with an obvious border. Photoshop CS 4 introduced more advanced edge control and you can even smooth it as well as feather it all in one menu box which is convenient.

There is also a plugin for PS at Neil Flemings site for galaxy images - power saturate, dust enhancement, and one other. They are free.
They work well.

The other technique is the inverted mask. Louie did a free tutorial of how to do this in the computer/software section. Its a very handy technique so you can apply corrections only to a specific thing that automatically
fades out the correction to the edges and applies more to brighter or dimmer areas depending on what you want to do.

Although for this image selective colour is all you need and choose magenta and adjust then choose blue or cyans and adjust will mainly simply change the galaxy without changing anything else as nothing else in your image has any colour. So no need to select it out really.
Or use the colour balance tool which is easier to use than selective colour. Selective colour is an awesome tool though to get the colours in your image just right and get rid of magenta bias (a common astroimage problem) etc. Its worth getting used to using it. Also in selective colour adjusting neutrals for magenta, cyan etc is very handy if you have an odd background colour (usually too much green). Another similar free tool is HLVG by Rogelio Andreo and that gets rid of green noise. Green noise is very common in the backgrounds of astro images. Getting rid of it can make a beautiful improvement to the appearance of the image, bringing out lovely bluish hues. Green usually looks yuck in astroimages, blue looks nice and red is good in small doses. Look at an astroimage and if it is dominated by red it tends not to be popular. Bluish tones are. Green should not be there as LRGB images are never green but of course we need it to balance out the colours but as I said it gets in through light pollution (predominantly green in colour) and LEDs from power transformers in our gear and I have even had gradients at my dark site under perfect conditions. Go figure. Maybe my injudicious use of a torch.

Stars are easiest done with the Carboni increase star colour action. Its fast and works well and no better done manually unless you have a colour bias in your stars which you would have to correct first before using it.

Sorry for the long post but there are many ways to skin a cat with Photoshop and thats why its such an awesome program.

Feel free to PM me and I am happy to give you detailed instructions on how to process your image with the best of what I know.

Greg.

[allan gould]

OK, I did some star colouring to the jpeg and I think this is the last itteration before I actually add the Luminance data with the QSI. I think with all the generous help I now have the techniques to go back and reprocess from the start and make a far better image. Many, many thanks to you all.
Comments welcomed

[allan gould]

Greg or any one else
Could you point me to this inverted mask routine as I have sarched but not found it.
Many thanks
Allan

[gregbradley]

Here you go:

http://www.atalas.net/index.php?option=com_expose&Itemid=4

I think its the one titled masks.

Greg.

[allan gould]

Thanks Greg, much appreciated. I PMed you and looking forward to your image.

[Paul Haese]

Getting there Allan. Lots of data there so keep working through it. It can be a tough road this processing game. I am liking each new image more than the previous.:thumbsup: