SL-17, Dark Wolf in Scorpius

[Geoff45 (Geoff)]

I took this one at the July Wiruna weekend. It was a little tricky to process and I thank Niall MacNeill and Dean Carr for helpful comments on a preliminary version.

The picture is here: https://www.astrobin.com/2bl82f/

Instrument details: Tele Vue NP101is, QSI 540wsg, Astro-Physics 900GTO

Processed in PixInsight

FOV: 85' x 60' (cropped)

[strongmanmike (Michael)]

Nice job Geoff, I guess many like the contrast but I really like the way you have revealed some gas and dust in the usually pretty black Wolf. Be nice to see slightly "shinier" more colourful stars perhaps? Well done though a good Wiruna catch

[Geoff45 (Geoff)]

Originally Posted by strongmanmike

Nice job Geoff, I guess many like the contrast but I really like the way you have revealed some gas and dust in the usually pretty black Wolf. Be nice to see slightly "shinier" more colourful stars perhaps? Well done though a good Wiruna catch

Thanks Mike. I agree about the stars. The difficulty arises from the way I processed the image. I pulled the stars off then processed the nebulosity and afterwards put the stars back. Sounds easy but it’s not. I was also trying to keep all the faint stars in the background so I didn’t push the star stretch too much, so when they got put back they were a bit muted by the bright nebulosity.

[strongmanmike (Michael)]

Originally Posted by Geoff45

Thanks Mike. I agree about the stars. The difficulty arises from the way I processed the image. I pulled the stars off then processed the nebulosity and afterwards put the stars back. Sounds easy but it’s not. I was also trying to keep all the faint stars in the background so I didn’t push the star stretch too much, so when they got put back they were a bit muted by the bright nebulosity.

Fair'nuf, yeah it's not as straight forward as one might think. After analysing 100's of deep sky astro entries recently for APP, I noticed this effect in a few images, it may be a result of similar approaches, involving star removal and replacing..? Characterised by muted star colours with no shine.

Mike

[petershah (Peter Shah)]

Nice work....not easy when removing stars

[gregbradley]

That turned out great Geoff. You got some nice contrast there between the Wolf and the Ha areas.

Interesting comments about the stars. Looking at it again I can see what is being referred to. Something to keep in mind in general with astro images.
The current trend is to remove the stars, process the neb then add the stars back in. A process probably a lot easier in Photoshop than PI.
But as a processing technique it opens the door to artificiality which is not desired.
Greg.

[Peter Ward]

Originally Posted by gregbradley

That turned out great Geoff. You got some nice contrast there between the Wolf and the Ha areas.

Interesting comments about the stars. Looking at it again I can see what is being referred to. Something to keep in mind in general with astro images.
The current trend is to remove the stars, process the neb then add the stars back in. A process probably a lot easier in Photoshop than PI.
But as a processing technique it opens the door to artificiality which is not desired.
Greg.

I think Greg's comments are on the money. This is a nice image but
does raise some interesting questions.

I am torn over the subduction of field stars to get a "look"....akin to blemish
free skin that has been photoshopped away from a model's face.

Would a landscape photographer remove leaves with software to better show the tree trunks?

Separate processing can often divorce the scene from reality.

Just because you can, doesn't mean you should.

[Geoff45 (Geoff)]

Hi Greg and Peter
This technique (separate the stars and the nebulosity for processing) is something I have been trying for my last three images. It definitely does give itself away unless great care is taken. This applies to various other techniques as well. Looking at many Astrobin images it is often obvious which ones have used BlurXTerminator or NoiseXTerminator and also the ones that have processed stars and nebulosity separately.

Peter, I really like your analogy of the leaves and the tree trunk.

On the other hand, people have been reducing the impact of stars for many years using traditional techniques, so this is just a new way of accomplishing a similar object.

As you say “torn”

[Andy01 (Andy)]

Love the 3D look and the depth previously unseen in dark nebulosity of this now very popular target. Although it's a little noisy, that's a great rendition of this object; well done!

[Geoff45 (Geoff)]

Thanks Andy

[strongmanmike (Michael)]

Originally Posted by Geoff45

Looking at many Astrobin images it is often obvious which ones have used BlurXTerminator or NoiseXTerminator and also the ones that have processed stars and nebulosity separately.

Yes, after closely analysing several hundred images recently, I'd have to agree on all counts Geoff. Like any seemingly holy grail like tool, they still need a deft hand to pull off believably

Mike

[Geoff45 (Geoff)]

Originally Posted by strongmanmike

Yes, after closely analysing several hundred images recently, I'd have to agree on all counts Geoff. Like any seemingly holy grail like tool, they still need a deft hand to pull off believably

Mike

Yep. The better the tool, the more pressure there is on the processor not to overuse it.