Eagle Nebula - Pillars of Creation

[Varavall]

 

Hi all

I have been gathering data over a couple of nights to try and capture the Pillars of Creation. I am working through night time temperatures of 22-25C, Saharan dust and a bright Moon, so far from ideal. This is using  SW 200pds, HEQ5 rowan belted, ASI1600MM-Cool, NINA for 2 hours each of Ha, Oiii and Sii at 5 minute subs, aligned and stacked in ASTAP and processed in GIMP. Any comments and suggestions as to the best Ha:Oiii:Sii ratio of subs for this target and useful critical comments regarding the image are more than welcome.

 

[Shibby]

Looks to me like you may have some good data there. I would say the colour balance is strange - very green. Also, the image looks clipped, possibly at both ends of the histogram. This may be a symptom of using GIMP, though - does GIMP still only have 8bit curve adjustments?

[AstroMuni]

On 11/07/2022 at 11:48, Varavall said:

Any comments and suggestions as to the best Ha:Oiii:Sii ratio of subs for this target and useful critical comments regarding the image are more than welcome.

I use a free tool called Siril for stacking and processing my images. Here is their tutorial for this https://siril.org/tutorials/rgb_composition/

Edited July 15, 2022 by AstroMuni

[Varavall]

On 15/07/2022 at 12:57, Shibby said:

I would say the colour balance is strange

I agree. I was trying to tease out as much contrast/detail in the pillars as I could and ended up with that. At the moment the big, bright moon is illuminating all the Saharan dust in the sky and has turned my Bortle 3 sky to a Bortle 7, just like being in the centre of Barcelona. Maybe when I get more data, I can tweak the colours better.

 

On 15/07/2022 at 12:57, Shibby said:

does GIMP still only have 8bit curve adjustments?

Yup

 

On 15/07/2022 at 12:57, Shibby said:

Looks to me like you may have some good data there.

That is a pleasing comment!

[Elp]

23 minutes ago, Varavall said:

I was trying to tease out as much contrast/detail in the pillars as I could

You could draw a mask around that particular area, feather the edge selection and just tweak that region which will help. Also the siril tutorials state something like not to clip the black more than 0.1 % when histogram stretching, I tend to go even stricter like no more than 0.01%. Don't bring down the white level either otherwise you'll clip the whites, adjust the midtone instead.

Its a simple thing but switching off any surrounding lights or processing at night helps a lot too, it's like the difference you see when watching TV with daylight coming though behind the TV, and seeing the same thing at night with no background illumination you can see more contrast differences.

Edited July 16, 2022 by Elp

[Varavall]

2 hours ago, Elp said:

You could draw a mask around that particular area, feather the edge selection and just tweak that region which will help.

Thanks for that. I'll give that a go.

2 hours ago, Elp said:

Its a simple thing but switching off any surrounding lights

I'd love too, but the nearest lights are 6 Km away and I don't think the town council will be obliging 🙄

[Elp]

4 minutes ago, Varavall said:

I'd love too

When you're post processing.

[Varavall]

6 minutes ago, Elp said:

When you're post processing.

Ah.....🤣

[Varavall]

On 15/07/2022 at 15:07, AstroMuni said:

I use a free tool called Siril

I have now had a look at Siril and after spending 2 hours of my life that I will never see again, I uninstalled it. It doesn't resonate with me, I'll look for some other software that I find intuitive. Horses for courses and this one isn't mine.

[AstroMuni]

38 minutes ago, Varavall said:

I have now had a look at Siril and after spending 2 hours of my life that I will never see again, I uninstalled it. It doesn't resonate with me, I'll look for some other software that I find intuitive. Horses for courses and this one isn't mine.

Sorry to hear that. Did you read the tutorials or went straight for it 🙂 Have a read here https://siril.org/tutorials/

[Varavall]

1 minute ago, AstroMuni said:

Did you read the tutorials

Yup, had a read and they had just as well have been written in Manadarin, so I clicked around for a bit and got nowhere. I find some software so easy, but this one draws a blank. Just how my brain works. I have considerable expertise in organic chemistry which I find so obvious, but for others it's a black art. Everyone's brains are different!

[AstroMuni]

I agree its not the most intuitive of software, but hey a lot of software is just that way... I simply followed the steps in https://siril.org/tutorials/tuto-scripts/
before it started making sense.