Placidus
15-02-2015, 03:54 PM
This Swan is from a couple years ago, with the old STL-11000M. I've reprocessed it knowing what I've learned in the interim.
Even back then, it was a quickie: 2hrs each SII (red), H-alpha (green), OIII (blue). There is a far deeper shot on APOD.
The biggest change in my approach is that I'm pushing the SII much more now, to try to show not how much SII there is (very little, so a green image), but where the SII is (so a more balanced image).
So what does the SII tell us? Every astro-photo is not just a pretty face, it is a story.
Notice the huge arc of red-orange-yellow SII arching up and around the top left of the image, starting perhaps somewhere around 8 o'clock, and finishing around 1 o'clock. For this web of material to be showing in SII, it has to be very thin, cool, material, dredged up from the hearts of probably now dead stars. The webbing suggests multiple tangled shock fronts, perhaps from old supernova explosions.
By comparison, the bottom right part of the image contains almost no SII, and shows much more green H-alpha. This green is code for thicker, hotter, and/or less recycled material.
Hugely pushing the SII (so that you can see this rare and valuable stuff) makes magenta haloes around stars. I've controlled the ones around the brighter stars, but as Bob Marley said, they are just a part of it. I've not tried to eliminate them completely.
Big one here. About 1MB. (http://www.mikeberthonjones.smugmug.com/Category/Star-Forming-Regions/i-QGc77Nq/0/O/0082%20Swan%20Ha%202%20OIII%202%20S II%202hrs.jpg)
Every picture tells a story, baby.
Even back then, it was a quickie: 2hrs each SII (red), H-alpha (green), OIII (blue). There is a far deeper shot on APOD.
The biggest change in my approach is that I'm pushing the SII much more now, to try to show not how much SII there is (very little, so a green image), but where the SII is (so a more balanced image).
So what does the SII tell us? Every astro-photo is not just a pretty face, it is a story.
Notice the huge arc of red-orange-yellow SII arching up and around the top left of the image, starting perhaps somewhere around 8 o'clock, and finishing around 1 o'clock. For this web of material to be showing in SII, it has to be very thin, cool, material, dredged up from the hearts of probably now dead stars. The webbing suggests multiple tangled shock fronts, perhaps from old supernova explosions.
By comparison, the bottom right part of the image contains almost no SII, and shows much more green H-alpha. This green is code for thicker, hotter, and/or less recycled material.
Hugely pushing the SII (so that you can see this rare and valuable stuff) makes magenta haloes around stars. I've controlled the ones around the brighter stars, but as Bob Marley said, they are just a part of it. I've not tried to eliminate them completely.
Big one here. About 1MB. (http://www.mikeberthonjones.smugmug.com/Category/Star-Forming-Regions/i-QGc77Nq/0/O/0082%20Swan%20Ha%202%20OIII%202%20S II%202hrs.jpg)
Every picture tells a story, baby.