The Swan/Omega Nebula

[MarsG76]

Hello astronomers,

Sharing with you all my latest rendition of the Swan/Omega Nebula - M17, imaged for 15 hours & 43 minutes during multiple nights between 26 June and 2 July 2020.

This was imaged through SII, HAlpha and OIII filters using my Celestron C8 8" SCT @ f6.3 with the astromodded and cooled Canon 40D DSLR, all riding on a CGEM.

These images are combined using the same data except one is SHO, Hubble Palette, style and the other is HOO to emulate natural color using the narrowband data.

 

Clear Skies,

MG

[ollypenrice]

Good stuff. I think the nebulosity is a great success. The stars, though, as is often the case with SCT deep sky images, are pretty large. Of late I've been seeing what happens when I use Starnet++ to de-star an image and then paste the original linear data on top of that in Photoshop's blend mode lighten before stretching that top layer till the stars begin to appear but in smaller size. It's quite simple and might work well with this data.

Olly

[x6gas]

Olly"s spot on and this is exactly the trouble I have when imaging with my SCT...

Lovely image nonetheless...

[mackiedlm]

On 12/07/2020 at 19:36, ollypenrice said:

Good stuff. I think the nebulosity is a great success. The stars, though, as is often the case with SCT deep sky images, are pretty large. Of late I've been seeing what happens when I use Starnet++ to de-star an image and then paste the original linear data on top of that in Photoshop's blend mode lighten before stretching that top layer till the stars begin to appear but in smaller size. It's quite simple and might work well with this data.

Olly

Olly,  I've been trying this without much success. Can you confirm, you process the image to almost complete, then remove stars, then put the linear image on top, blend mode lighten, then stretch with curves till you get the stars right, is that right or am I missing something. Thanks.

Fantastic images MG.

[MarsG76]

On 13/07/2020 at 04:36, ollypenrice said:

Good stuff. I think the nebulosity is a great success. The stars, though, as is often the case with SCT deep sky images, are pretty large. Of late I've been seeing what happens when I use Starnet++ to de-star an image and then paste the original linear data on top of that in Photoshop's blend mode lighten before stretching that top layer till the stars begin to appear but in smaller size. It's quite simple and might work well with this data.

Olly

Thank for the tip... I'll give Starnet++ a go... perhaps thats my next step in AP, star bloat control.

 

[Hallingskies]

On 12/07/2020 at 19:36, ollypenrice said:

Good stuff. I think the nebulosity is a great success. The stars, though, as is often the case with SCT deep sky images, are pretty large. Of late I've been seeing what happens when I use Starnet++ to de-star an image and then paste the original linear data on top of that in Photoshop's blend mode lighten before stretching that top layer till the stars begin to appear but in smaller size. It's quite simple and might work well with this data.

Olly

That works for me really well too, but I find I sometimes have to apply a tiny bit of Gaussian blur (0.7 or so) to the star layer to avoid the stars looking “painted in”.  

Hardest problem I had with Starnet was finding a computer in the house that it actually ran on. But for the price you pay for it...

 

[ollypenrice]

11 hours ago, Hallingskies said:

That works for me really well too, but I find I sometimes have to apply a tiny bit of Gaussian blur (0.7 or so) to the star layer to avoid the stars looking “painted in”.  

Hardest problem I had with Starnet was finding a computer in the house that it actually ran on. But for the price you pay for it...

 

It might be worth applying a custom stretch to the linear star layer to avoid the 'painted in' look. I haven't tried it but my guess would be to lift the bottom of the curve and restore it to a straight line low down, so softening the stellar edges. I think that just one mild application of such a stretch might be the thing before returning to the standard log stretch.

Olly

[MarsG76]

On 13/07/2020 at 04:36, ollypenrice said:

Good stuff. I think the nebulosity is a great success. The stars, though, as is often the case with SCT deep sky images, are pretty large. Of late I've been seeing what happens when I use Starnet++ to de-star an image and then paste the original linear data on top of that in Photoshop's blend mode lighten before stretching that top layer till the stars begin to appear but in smaller size. It's quite simple and might work well with this data.

Olly

OK, I played with Starnet ++ and it definitely has potential. Definitely a tool I'll be using in the future, especially with capturing and adding RGB color stars to my Narrowband imaging.

It very easy to control the intensity and color of stars and now, thanks to your tip, I can process stars and nebulosity/DSO separately.

Attached is my result after a quick play after work. I tried to not be too rough with the stars but they do look more "delicate" IMHO.

Thanks Olly.

 

Edited July 16, 2020 by MarsG76