M101 feedback

[bottletopburly]

my version skipped  a few modules just to see, so autodev ,wipe ,autodev,contrast ,colour ,noise reduction 4.0 pixels 

 

[vlaiv]

2 hours ago, Pitch Black Skies said:

It would be great to find out how I can produce something similar with just Startools.

I don't use star tools so can't be of a help there, but @alacant might be able to give you walk thru / step by step guide?

[Pitch Black Skies]

1 hour ago, alacant said:

For the second AutoDev, you are selecting neither a region of interest nor setting the gamma, fine detail or shadows, after which the stars and background will be taken care of.

HTH

Is it just a matter of playing around with those settings until it looks pleasing to the eye?

I've just tried cropping in with the ROI levels and it reduced the stretch considerably, so made a huge difference. I didn't touch gamma, shadows and fine detail.

TY

[Pitch Black Skies]

57 minutes ago, bottletopburly said:

my version skipped  a few modules just to see, so autodev ,wipe ,autodev,contrast ,colour ,noise reduction 4.0 pixels 

 

Yeah that wouldn't be my cup of tea. Definitely an improvement over mine though.

[Pitch Black Skies]

1 hour ago, Budgie1 said:

Not really helpful if you're using StarTools but, I ran your image through PixInsight to see that I could get with the data and here's the result.

 

That's really nice. Great detail in the core. Background light level looks good.

[symmetal]

Here's my effort using Startools and ( PS to lift the background). Not so much noise reduction but that's a personal thing. The Spacially Variant PSF Decon has made spots in the bright stars but I used the default mask. I usually just create a second blurred layer in PS and soft edge mask in the blurred version over the star centres

Alan

[Pitch Black Skies]

24 minutes ago, symmetal said:

Here's my effort using Startools and ( PS to lift the background). Not so much noise reduction but that's a personal thing. The Spacially Variant PSF Decon has made spots in the bright stars but I used the default mask. I usually just create a second blurred layer in PS and soft edge mask in the blurred version over the star centres

Alan

That's pretty cool.

[Pitch Black Skies]

Definitely a bit of an improvement here I think..

Before

 

After

Edited April 4, 2022 by Pitch Black Skies

[Pitch Black Skies]

19 hours ago, alacant said:

 

StarTools 1.8.527mr2

Nice detail but still quite a bit of noise considering there's 19 hours. Are you dithering between frames and stacking with a clipping algorithm?

If you want the Ha regions, stick the red in NBAccent.

 

 

 

 

Really nice,

Yes I dither between every frame.

These are the settings I use in DSS;

 

[Pitch Black Skies]

@alacant I've noticed that I am saving the file as 16 bit FITS rather than the recommend 32 bit FITS integer.

Edited April 4, 2022 by Pitch Black Skies

[alacant]

25 minutes ago, Pitch Black Skies said:

the settings

Don't know that app, but I'd recommend using flat frames as a very minimum. I'd guess maybe the 533 doesn't need dark frames (?) as you don't specify those either. 

Have a look at Siril which defaults to 32 bit and has a far more comprehensive set of calibration and stacking options.

Cheers

Edited April 4, 2022 by alacant

[vlaiv]

42 minutes ago, Pitch Black Skies said:

These are the settings I use in DSS;

Apart from not using calibration files, if you are going to use kappa sigma clip stacking method - you need to perform background calibration for it to work properly.

[Pitch Black Skies]

1 hour ago, alacant said:

Don't know that app

It's the one Startools promotes on the Startools website, it's really popular.

 

1 hour ago, alacant said:

but I'd recommend using flat frames as a very minimum

The file I loaded into DSS is the fully calibrated finished file of 19hrs. It was just to show you the settings I use. Ignore the prompts about no darks, flats, bias, etc.

Edited April 4, 2022 by Pitch Black Skies

[Pitch Black Skies]

39 minutes ago, vlaiv said:

Apart from not using calibration files

Calibration frames were used. What you're looking at there is the finished file of 19hrs fully calibrated. DSS is detecting it as a single light hence the prompts for calibration frames.

42 minutes ago, vlaiv said:

if you are going to use kappa sigma clip stacking method - you need to perform background calibration for it to work properly.

On the Startools website it advises to use Kappa Sigma if stacking more than 20 frames. It also advised to turn off any sort of Background Calibration..

[vlaiv]

17 minutes ago, Pitch Black Skies said:

On the Startools website it advises to use Kappa Sigma if stacking more than 20 frames. It also advised to turn off any sort of Background Calibration..

Kappa Sigma stacking is good method of stacking, but it really needs normalized frames.

It looks at pixel statistics to be able to detect anomalous pixel values - like hot pixels or satellite trails.

In order to form good statistics of pixel values - all subs must be normalized. As night progresses and you track target across the sky - few things happen:

- target moves across the sky and raises and sets (depending on side of meridian at any particular moment) - this means that target is changing altitude - sometimes it is closer to horizon and sometimes to zenith.

There is something called air-mass - that determines how much attenuation there will be by atmosphere. For same transparency - air mass is factor that determines how much effect that transparency has on target.

It boils down that same target can be brighter and less bright - depending where in the sky it is positioned.

- another thing that happens is that there is changing amount of light pollution. People turn lights / on and off depending on the time of night, and as target moves - it changes direction with respect to you and there are different levels of LP depending on direction (it is very rarely uniform).

In any case - subs will have different target brightness and different background levels. Same target pixel will end up being brighter or less bright depending on these. This makes it difficult for algorithm to properly guess if pixel is hot pixel / satellite trail or simply brighter because of transparency or light pollution.

Ideally - you want to do linear fit between subs (transparency is multiplicative while LP is additive so it turns into nice linear equation ax+b), or at least do what DSS is doing - to equalize median pixel values (just additive normalization).

DSS technical info page clearly states this:

http://deepskystacker.free.fr/english/technical.htm#Stacking

Quote

It is important to check one of these options when using Kappa-Sigma Clipping or Kappa-Sigma Clipping Median methods to ensure that the pictures being stacked have all the same background value.

 

[alacant]

56 minutes ago, Pitch Black Skies said:

it's really popular

The StarTools site lists recommended settings for dss. I can find no promotion for the app on the site. Windows users tell me it's quite dated. There are alternatives;) 

Edited April 4, 2022 by alacant

[tomato]

Here is my version processed in StarTools. This is using AutoDev rather than FilmDev after the Wipe module. I can't see much wrong with your original calibrated and stacked file,  I use APP for this , but I don't think DSS did a bad job.

[Pitch Black Skies]

2 hours ago, vlaiv said:

Kappa Sigma stacking is good method of stacking, but it really needs normalized frames.

It looks at pixel statistics to be able to detect anomalous pixel values - like hot pixels or satellite trails.

In order to form good statistics of pixel values - all subs must be normalized. As night progresses and you track target across the sky - few things happen:

- target moves across the sky and raises and sets (depending on side of meridian at any particular moment) - this means that target is changing altitude - sometimes it is closer to horizon and sometimes to zenith.

There is something called air-mass - that determines how much attenuation there will be by atmosphere. For same transparency - air mass is factor that determines how much effect that transparency has on target.

It boils down that same target can be brighter and less bright - depending where in the sky it is positioned.

- another thing that happens is that there is changing amount of light pollution. People turn lights / on and off depending on the time of night, and as target moves - it changes direction with respect to you and there are different levels of LP depending on direction (it is very rarely uniform).

In any case - subs will have different target brightness and different background levels. Same target pixel will end up being brighter or less bright depending on these. This makes it difficult for algorithm to properly guess if pixel is hot pixel / satellite trail or simply brighter because of transparency or light pollution.

Ideally - you want to do linear fit between subs (transparency is multiplicative while LP is additive so it turns into nice linear equation ax+b), or at least do what DSS is doing - to equalize median pixel values (just additive normalization).

DSS technical info page clearly states this:

http://deepskystacker.free.fr/english/technical.htm#Stacking

 

Okay, I'll try linear fit option instead or Kappa Sigma with background calibration and see what happens.

[Pitch Black Skies]

2 hours ago, alacant said:

The StarTools site lists recommended settings for dss. I can find no promotion for the app on the site. Windows users tell me it's quite dated. There are alternatives;) 

Cool, I'll check out Siril.

[Pitch Black Skies]

14 hours ago, tomato said:

Here is my version processed in StarTools. This is using AutoDev rather than FilmDev after the Wipe module. I can't see much wrong with your original calibrated and stacked file,  I use APP for this , but I don't think DSS did a bad job.

Yeah that's pretty nice, stars nice and tight.

Still has that Startools look to it though, I can't explain it.

Edited April 5, 2022 by Pitch Black Skies

[vlaiv]

5 minutes ago, Pitch Black Skies said:

Okay, I'll try linear fit option instead or Kappa Sigma with background calibration and see what happens.

DSS does not implement linear fit for frame normalization - only what they call "background calibration" and is in essence constant fit rather than linear.

[powerlord]

I use startools. I also use siril and affinity photo. Most of the time I find I get better results with siril and affinity photo.

I think this is mainly down to the fact that in affinity photo it can all be non destructive and layered. I can use starnet2++ and work on the image, etc. If something isn't quite right, reduce it, etc.

startools I find I just sort of go through the options in order, with limited success, and at the end either it works - great. or it doesn't.. in which case, tough.. nothing to do but start again.

I also find startools denoise to be really bad compared to even affinity photo, but I use topaz which is light years ahead.

affinity photo is available as a trial and is cheap anyway. topaz no so much, but they do do deals - I think I got the whole suite for 40 quid. I hate PI as a matter of principle - its licencing model, price, attitude of the company and its utterly aborrent UI design. Plus affinity photo isn't a one trick pony - it's great for all photography work. give it a go ?

I really wish Stefan would add starnet2++ integration to startools. I think it would help a lot. As it is, it is just too downright weird most of the time how it processes my stacked image.

stu

Edited April 4, 2022 by powerlord

[Pitch Black Skies]

59 minutes ago, vlaiv said:

DSS does not implement linear fit for frame normalization - only what they call "background calibration" and is in essence constant fit rather than linear.

Would you recommend trying a different software?

You seemed to be able to get a cracking result with the DSS file.

[Pitch Black Skies]

Improvement?

[Jamgood]

@Pitch Black Skies You sound like you're like me. I always struggle with Galaxies. I find them really difficult to process and I'm never or rarely happy with the result.

I recently upgraded to Astro pixel processor for stacking. You could give the trial version of that a go. It's a bit daunting at first but when you get it, it is a nice powerful tool.