Help with galaxy processing (NGC 3628)

[StuartT]

This is the result of three sessions (9h total integration time) processed in APP then tweaked in PI and Photoshop, but I am not sure of my technique and wondered if anyone might be able to squeeze anything further out of my data? I attach the stacked FITS file. 

Thank you!

 

NGC_3628_third_session-session_1_session_2_session_3.fits

[mackiedlm]

Sorry Stuart, I could not get past gradient removal. I was producing the most horrendous background using my whole arsenal of ABE, DBE and LP removal in APP.  I Really donk know why that is because you've got a nice BG in yours.

[StuartT]

19 minutes ago, mackiedlm said:

Sorry Stuart, I could not get past gradient removal. I was producing the most horrendous background using my whole arsenal of ABE, DBE and LP removal in APP.  I Really donk know why that is because you've got a nice BG in yours.

no worries. Thanks for trying.

Let me give you a tip - Astro Flats Pro. It's a truly amazing Photoshop plugin. I always use it as my final step https://www.prodigitalsoftware.com/AstroFlatPro1_News.html 

WAY better than Gradient Exterminator

Edited March 25, 2022 by StuartT

[tooth_dr]

12 hours ago, StuartT said:

no worries. Thanks for trying.

Let me give you a tip - Astro Flats Pro. It's a truly amazing Photoshop plugin. I always use it as my final step https://www.prodigitalsoftware.com/AstroFlatPro1_News.html 

WAY better than Gradient Exterminator

Hi Stuart

At what point do you use this gradient removal plugin?  Currently I use APP but do find it can be a bit hit and miss, although generally good.  In APP it’s done early on with the data still linear, before background/star colour calibration. Looks like it’s done here on an already stretched image?

 

Thanks

Adam. 

[StuartT]

2 hours ago, tooth_dr said:

Hi Stuart

At what point do you use this gradient removal plugin?  Currently I use APP but do find it can be a bit hit and miss, although generally good.  In APP it’s done early on with the data still linear, before background/star colour calibration. Looks like it’s done here on an already stretched image?

 

Thanks

Adam. 

As I said in my post. It's the final step. It's really great!

Edited March 26, 2022 by StuartT

[bottletopburly]

 Thanks for sharing stuart  had a play in startools ,horrendous gradients though ,is that being caused by your flats ? didnt come out too bad though. 

[StuartT]

21 hours ago, bottletopburly said:

 Thanks for sharing stuart  had a play in startools ,horrendous gradients though ,is that being caused by your flats ? didnt come out too bad though. 

thanks!

Not sure why such a gradient. I made 20 flats as usual.

[tooth_dr]

On 26/03/2022 at 10:40, StuartT said:

As I said in my post. It's the final step. It's really great!

Ok didn’t read that bit, see that now. If it’s works 👍🏼

[wimvb]

Pixinsighted

• Dynamic Crop
• DBE
• Background Neutralization
• Photometric Color Calibration
• Arcsinh stretch
• Curves Transformation
• Multiscale Median Transform with bias on L with mask to protect the stars

How are your imaging conditions? Light pollution can be the cause of weird gradients. As can a lot of other things, of course.

Edited March 28, 2022 by wimvb

[tomato]

Here is my effort processed in  APP using the Remove light pollution tool at the linear stage and then the background removal tool in Affinity Photo on the stretched image. 

Edited March 28, 2022 by tomato

[StuartT]

3 hours ago, wimvb said:

Pixinsighted

• Dynamic Crop
• DBE
• Background Neutralization
• Photometric Color Calibration
• Arcsinh stretch
• Curves Transformation
• Multiscale Median Transform with bias on L with mask to protect the stars

How are your imaging conditions? Light pollution can be the cause of weird gradients. As can a lot of other things, of course.

 

1 hour ago, tomato said:

Here is my effort processed in  APP using the Remove light pollution tool at the linear stage and then the background removal tool in Affinity Photo on the stretched image. 

Thanks guys! I like these very much.

One thing I've not attempted yet is deconvolution, which might help a bit. Though I think it can make noise worse.

[wimvb]

50 minutes ago, StuartT said:

 

Thanks guys! I like these very much.

One thing I've not attempted yet is deconvolution, which might help a bit. Though I think it can make noise worse.

I don't think it will make matters worse, because you will mask the background anyway. If you want to use deconvolution, it works best on clean luminance.

[StuartT]

36 minutes ago, wimvb said:

I don't think it will make matters worse, because you will mask the background anyway. If you want to use deconvolution, it works best on clean luminance.

Not sure I know what you mean by 'clean luminance' - I only shoot with an OSC (prob should have mentioned that)

[wimvb]

26 minutes ago, StuartT said:

Not sure I know what you mean by 'clean luminance' - I only shoot with an OSC (prob should have mentioned that)

Yes, I saw that in your signature. You can extract luminance from the colour image while it is still linear and apply deconvolution to that. (This is what I meant by "clean luminance", as opposed to the rgb channels which also contain lightness or luminance information.) Then use LRGB combination to put the luminance back. You can even process the colour image just for colour, stretch the luminance for detail and reinsert it with LRGB combination.

For deconvolution to give any benefit, you need a high signal to noise ratio. Like any other sharpening technique, deconvolution tends to increase noise.

[StuartT]

1 hour ago, wimvb said:

Yes, I saw that in your signature. You can extract luminance from the colour image while it is still linear and apply deconvolution to that. (This is what I meant by "clean luminance", as opposed to the rgb channels which also contain lightness or luminance information.) Then use LRGB combination to put the luminance back. You can even process the colour image just for colour, stretch the luminance for detail and reinsert it with LRGB combination.

For deconvolution to give any benefit, you need a high signal to noise ratio. Like any other sharpening technique, deconvolution tends to increase noise.

Thanks. That's really helpful. I'm going to try that

[gorann]

On 25/03/2022 at 20:25, StuartT said:

no worries. Thanks for trying.

Let me give you a tip - Astro Flats Pro. It's a truly amazing Photoshop plugin. I always use it as my final step https://www.prodigitalsoftware.com/AstroFlatPro1_News.html 

WAY better than Gradient Exterminator

Sounds like a great PS plug-in, but as often I see that it will not work on a Mac🥴

[wimvb]

1 hour ago, gorann said:

Sounds like a great PS plug-in, but as often I see that it will not work on a Mac🥴

PixInsight does 😜

but you already knew that

Edited March 29, 2022 by wimvb

[lukebl]

On 25/03/2022 at 19:25, StuartT said:

Let me give you a tip - Astro Flats Pro. It's a truly amazing Photoshop plugin. I always use it as my final step https://www.prodigitalsoftware.com/AstroFlatPro1_News.html 

WAY better than Gradient Exterminator

Thanks for that tip. Never heard of that Plugin before. I've just given it a try and it's a complete game-changer!

As you say, WAAAAY better than GradientXterminator. It's particularly good at uneven and blotchy gradients, which GradientXterminator can't deal with.

Edited March 29, 2022 by lukebl

[StuartT]

2 hours ago, lukebl said:

Thanks for that tip. Never heard of that Plugin before. I've just given it a try and it's a complete game-changer!

As you say, WAAAAY better than GradientXterminator. It's particularly good at uneven and blotchy gradients, which GradientXterminator can't deal with.

Glad you like it! It really should be better known about!