Transatlantic Jellyfish

[gorann]

Now, when I finally have some clear skies, the moon spoils it all, so I have played around with data from last month on the Jellyfish Nebula. It is my DSLR data with Francois Theriault's CCD Ha data as luminosity.

Equipment in Sweden: ES 127ED refractor with TS 0.79x reducer (=f/5.9) IDAS filter and Canon 60Da on EQ8. Equipment in Canada Antares 8" Newtonean (f/5) and SBIG ST8300M and Bader Ha 7nm filter on CGEM.

65 x 300" exposures = 5.4 hours

[laudropb]

Very nice image.

[swag72]

For me this is too bright, so bright I would say that you are starting to lose detail within the Jellyfish. There's also a significant vignette. The whole thing has just been pushed too far for my tastes I'm afraid.

[ollypenrice]

Yes, I'd ease it down as well, and I wouldn't use Ha as lum. I'd try it in red and blend mode lighten. If you can get an OIII layer to lighten green and blue you'll love it!

Olly

[gorann]

Thanks for the suggestions, I see what you mean. We had a dinner party tonight but I will have a go at it tomorrow

Cheers

[gorann]

Sara & Olly

I have done some processing this morning while slowly recovering from last night's party. Here is first a version with Ha mixed into the red channel as suggested by Olly, followed by a mix between this new version and the previous. For some reasons gradients become more apparent after uploading the images here. They are hard for me to see in Photoshop.

Comments most welcome.

[gorann]

Here is a version which I hope shows less gradients

 

[swag72]

What does your histogram looks like? The background looks clipped to me

[gorann]

51 minutes ago, swag72 said:

What does your histogram looks like? The background looks clipped to me

Here are the histograms in Photoshop. Using the eyedropper to probe the background gives RGB values between of 15-20 in the corners.

[gorann]

Here is a version where I now have taken care not to clip the dark areas. I still have these dark "holes" inside the jellyfish so they seem to be real in my data. Histograms enclosed.

[Barry-Wilson]

To my eye and monitor there are still residual gradients in the background Goran. I also think that you have pushed the data too far and have lost detail in the nebula structure which you patiently collected when imaging.

I sometimes find that continuing to refine an image and correct some processing 'flaw' can make matters worse and it can better to start again (though this objectivity is hard to find if you have been concentrating your efforts in one process route).

IMHO you have good data here and a fresh start may help - take a breath of fresh air and clear your mind before starting again would be my advice - and let your data reveal the hard one splendour of your capture.

[gorann]

Hi Barry

I am sure you are right but before I go for a walk with the dog I post this cropped version where I added back some Ha to the luminosity. I like the hairy texture it brings to the jellyfish head. One problem is that I do not have Ha data for the lowest parts of the jellyfish so those tentacles are more blurry that the head.

[gorann]

One thing I immediately saw after taking some fresh air is that the last post was much too bright. And I know why: I had the computer in front of a sunny window so I was trying to compensate for the light in the room. Here is a calmer version.

[swag72]

For me the bother here is the background. Your histograms don't looked clipped as you've posted, but there's something not right about it to me eye - It looks too solid and while it has some gradients, it's deviod of anything but really solid colour. I'm not sure that I've explained myself well. 

 

[gorann]

11 minutes ago, swag72 said:

For me the bother here is the background. Your histograms don't looked clipped as you've posted, but there's something not right about it to me eye - It looks too solid and while it has some gradients, it's deviod of anything but really solid colour. I'm not sure that I've explained myself well. 

 

I think I may know what you mean Sara. When I zoom in there is actually almost no noise there. I will go back to some of the versions I saved while processing to see what may have happened. Normally, my problem is the opposite: too much noise in the sky.

[gorann]

44 minutes ago, swag72 said:

For me the bother here is the background. Your histograms don't looked clipped as you've posted, but there's something not right about it to me eye - It looks too solid and while it has some gradients, it's deviod of anything but really solid colour. I'm not sure that I've explained myself well. 

 

Sara, I went back to an earlier version and found a more natural background - I must have clipped it at some later stage and lost many faint stars. Thank you very much for the input. I hope you think this version looks slightly better?

[gorann]

PS. I can see that I got some gradient issues coming back, but I can fix that.