Heart Nebula Processing Help...

[Astro Waves]

So couple weeks ago I managed to get a decent shot of the Heart Nebula which I was really happy but the thing I'm struggling with is the amount of stars. As soon as I start processing they just pop out like nobodies business and take over the image, this makes it a struggle to keep teasing out more detail in the nebula its self, is something like this more down to camera settings or processing for star reduction or a bit of both? 

This image has been stacked in Siril with a few adjustments done in that.

Bortle 4, no filters

x42 Lights - 210 Seconds

x11 Darks - 210 Seconds

x30 Flats - 1/25 Second

x50 Biases - 1/4000 Second

[CloudMagnet]

Quick trick in photoshop is to use the colour range selector (Select-> Colour range) . Use maximum fuzziness and range (200 and 100%) and use the dropper to select a bright star.

Then go to Select -> Modify -> Expand and increase this by around 2px. You might need to play around to get the best result with this.

Then press Ctrl+H to hide the marching ants. Finally go to Filter -> Other -> Minimum. On the radius, I find anything from 0.3 up to around 6 gives good results. Higher radius will lead to less stars, but at a risk of creating dark halos that dont look very good. Toggle the preview to compare the before and after.

Also dont forget to turn on the marching ants again or you will forget you only have the stars selected

Before and after (using a radius of 6.5 so fairly extreme):

 

 

Edited May 12, 2021 by CloudMagnet

[Astro Caller]

34 minutes ago, Astro Waves said:

So couple weeks ago I managed to get a decent shot of the Heart Nebula which I was really happy but the thing I'm struggling with is the amount of stars. As soon as I start processing they just pop out like nobodies business and take over the image, this makes it a struggle to keep teasing out more detail in the nebula its self, is something like this more down to camera settings or processing for star reduction or a bit of both? 

This image has been stacked in Siril with a few adjustments done in that.

Bortle 4, no filters

x42 Lights - 210 Seconds

x11 Darks - 210 Seconds

x30 Flats - 1/25 Second

x50 Biases - 1/4000 Second

would you mind sharing your data ? are you using Pixinsight or Photoshop? 

[Ollyb]

I used ‘Make Stars Smaller’ followed by ‘Enhance DSO, Make Stars Smaller’ in the Astronomy Tools Plug-In for Photoshop... 

I found it better to do this at the start of the processing, aster initial stretching, curves etc...

 

[Astro Caller]

6 minutes ago, Ollyb said:

I used ‘Make Stars Smaller’ followed by ‘Enhance DSO, Make Stars Smaller’ in the Astronomy Tools Plug-In for Photoshop... 

I found it better to do this at the start of the processing, aster initial stretching, curves etc...

 

Are you using masks? you need to sperate the background, stars and nebulosity and make adjustments, on this image you have clipped the dark reference  removing data from the image   

[Astro Caller]

3 minutes ago, Ollyb said:

This is an image of my stacked file, before doing star reduction in Photoshop...

Sorry adjusted post wrong person 

Edited May 12, 2021 by Astro Caller
incorrect person

[Ollyb]

26 minutes ago, Ollyb said:

 

Hi, sorry sent wrong image here in previous post...

my stacked TIFF is too large to email to you (67mb) but here is what it looks like after 1 level stretch in Photoshop...

[Astro Caller]

1 minute ago, Ollyb said:

Hi, sorry sent wrong image here in previous post...

my stacked TIFF is too large to email to you (67mb) but here is what it looks like after 1 level stretch in Photoshop...

No worries, I always use WeTransfer to send files, i don't use photoshop for main processing, just final touch ups, all my main processing is done in Pixinsight, but this image looks really good, nicely balanced, low noise 

[Ollyb]

6 minutes ago, Astro Caller said:

No worries, I always use WeTransfer to send files, i don't use photoshop for main processing, just final touch ups, all my main processing is done in Pixinsight, but this image looks really good, nicely balanced, low noise 

The red colour image was made with virtually just Ha as I have yet to collect sufficient Oiii and Sii to make a’ balanced’ RGB image... so it will be much better eventually.

I guess using a mono camera does make a big difference, I only need to use Darks to get rid of amp noise and I also use AstroFlat Pro in Photoshop but, actually, could probably not bother. This narrowband image is produced almost entirely from the above Ha Stack...

Good luck with reducing those stars!

[Ollyb]

48 minutes ago, Astro Caller said:

Are you using masks? you need to sperate the background, stars and nebulosity and make adjustments, on this image you have clipped the dark reference  removing data from the image   

Yes, I know the image has lost some data, it’s work in progress on the Heart Nebula... 

Believe it or not, I used Star Reduction here!...

[newbie alert]

Starnett++ Is your friend here 

[alacant]

On 12/05/2021 at 22:25, Astro Waves said:

they just pop out

Hi

I think you missed focus, so the stars look larger than need be.

HTH

[ollypenrice]

I agree that focus may be out, exacerbating the problem. Star control is a perennial problem. The closest I know to one-method solution is to stretch the image and then run it through (free) Starnet++  to de-star it. Next take the linear image (in RGB only if you use mono or just in one shot colour if not) and paste it on top of the starless one in Ps. Change the blend mode to Lighten and now all you'll see is the starless bottom layer. Slowly log stretch the top layer and the stars will gradually appear. Stop stretching when they are a size you like.

Olly

[Astro Waves]

Hi everyone, 

Thanks for getting back to me. Had a busy weekend and only just had chance to sit down and have a read through this. 

I've tried this technique (but I'm using Affinity Photo) and the result don't seem particularly smooth even if I play around with the settings but I don't think you get as much fine tuning options really.

On 12/05/2021 at 21:57, CloudMagnet said:

Quick trick in photoshop is to use the colour range selector (Select-> Colour range) . Use maximum fuzziness and range (200 and 100%) and use the dropper to select a bright star.

Then go to Select -> Modify -> Expand and increase this by around 2px. You might need to play around to get the best result with this.

Then press Ctrl+H to hide the marching ants. Finally go to Filter -> Other -> Minimum. On the radius, I find anything from 0.3 up to around 6 gives good results. Higher radius will lead to less stars, but at a risk of creating dark halos that dont look very good. Toggle the preview to compare the before and after.

 

 

 

I'm more than happy to share my data on this, whats the best way to go about doing that? Also I'm using Affinity Photo. 

On 12/05/2021 at 22:00, Astro Caller said:

would you mind sharing your data ? are you using Pixinsight or Photoshop? 

Yeah it is a bit out, I was shooting another target then the cloud rolled in so though I'd switch but didn't refocus as I was a tad tired but wanted to have a go at the heat nebula.

9 hours ago, alacant said:

Hi

I think you missed focus, so the stars look larger than need be.

HTH

The skies actually cleared last night which is a bloody miracle (for up here at the moment any way) so I was excited to shoot and thought I'd had a go at the Eastern Veil but sadly I kinda missed the majority of it but yet again tons of stars in that as well. Definitely need to figure out how to get the reduction on the go. Due to lots of faffing and trying to get a good place to shoot from/it being dam cold, I didn't get any way near as much data on it as I wanted to.  

[CloudMagnet]

22 hours ago, Astro Waves said:

I'm more than happy to share my data on this, whats the best way to go about doing that? Also I'm using Affinity Photo.

Its just a photoshop trick, I've not used Affinity before so I can't say if there as a similar process you can follow or if there are other settings you need to play around with as well.