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Peter Ward
25-05-2019, 11:48 PM
I had explored the whole "starless" thing many years ago and have now tinkered with Starnett++ on a few recent images....to see what it might and might not... do for them.

Then I ran Starnet++ over my recent Ha data with a similar field to Andy's post.

I was amazed how the presence of many Bok globules became much clearer plus planetary nebula or two.

I thought "surreal" and "not too shabby after all"

The link is here (http://www.atscope.com.au/BRO/gallery469.html)

Frank and fearless comments are welcome...

Placidus
26-05-2019, 07:02 AM
Excellent data to start with, and the star removal worked remarkably well.

One justification might be that the bulk of the visible stars are well in front of the nebulosity, not actually a part of it, and not behind it either, as the dust is relatively opaque. Thus the star removal shows what the nebulosity might look like if we were out there, very close to it, with the bulk of the visible stars behind us.

A philosophical thought: if there was a very bright star, burning out to a radius large compared with the seeing, then detail out to that radius would be forever lost, because the information was not in the original photo. To be able to reconstruct a starless image even in principle, we require a very sharp original image, such as you have taken, and stars that are not burned out to any appreciable distance relative to the seeing.

gregbradley
26-05-2019, 09:03 AM
Remarkable detail. I like it.

Greg.

Peter Ward
26-05-2019, 11:54 AM
I think there is some logic to that. I tried various colour images and was confronted with artifact central. Tight h-alpha data worked best for me. That said in the original 4k file, there was clear artifacting from the star removal routine. With a little Gaussian blur and just under 50% web resolution it cleaned up quite nicely.

Thanks Greg. The process has been around for a time
I recall reading about a photoshop method over a decade ago, which was picked up by Fred Vanderhaven who did well at the Malin awards with a "starless" image.

Starnet++ automates the process and certainly works well...but I think you need to pick the right data set for it to enhance the image rather than become a fashion statement.

leon
26-05-2019, 02:30 PM
Now that is very nice indeed, looks like a raging fire, well done.

Leon

Andy01
26-05-2019, 02:44 PM
A very nice result Peter. :thumbsup:

I've been staring at my starless rendition used to create the colour version just posted, and your details are certainly sharper - (a credit to your optics & skills).

Starless images need to have just the the right subject to work well too, as some certainly look better that others! :question:

Nice use of the technique :)

Peter Ward
26-05-2019, 08:20 PM
Thanks gentlemen. I'm not sure I'll be making a habit of starless processing, but in this instance it seemed to work well.

Stevec35
26-05-2019, 08:30 PM
Very artistic Peter. The effect is certainly similar to a raging fire.

Cheers

Steve

Peter Ward
27-05-2019, 09:00 AM
Thanks Steve. Well..it certainly looks like something...basket-baller avoiding a fire in a western wagon? :)

multiweb
27-05-2019, 09:46 AM
Pretty cool Peter. Super sharp and contrasty. :thumbsup:

Peter Ward
27-05-2019, 08:22 PM
Thank you Marc.

The Alluna does a nice job on H-alpha... often approximating it's theoretical spot sizes of around 5 micron...which to be realistic, even on a good night, is double that, due the typical seeing at sea-level.

That said, there is a filigree structure in the nebulosity of the "starless" version that is masked with the "star" version.

I'm not a fanboy of the process as yet, but now see it can have merit.

Atmos
27-05-2019, 08:40 PM
The contrast in the starless version of this is fantastic Peter, would love to see a SHO version, there are some tiny knots as you mention that do get obscured by stars.

Retrograde
27-05-2019, 10:38 PM
This starless thing is spreading like a disease.... :lol:

Fabulous detail Peter, just fabulous. The starless rendition really allows you to see every last knot and twist.

Peter Ward
28-05-2019, 02:10 PM
Thanks. BTW I have had my Flu jab :)



Ta, but, I don't think I'll do a SHO version.
Andy might do one...and if he does don't forget your sunnies :D