The Crescent Nebula (NGC 6888) in RGBHα
I used a stack of 13 4 minute exposures for the RGB component, and a stack of 20 3 minute hydrogen-alpha exposures as an enhancement for the red channel. I'm not sure what I was thinking when I was shooting emission nebulae without the Hα layer - the amount of detail it brings out is pretty incredible.
We're all waiting for the next supernova in the Milky Way. It's been centuries since the last one visible to the naked eye (unless you count 1987A - but that wasn't in the Milky Way). We've all read about Betelgeuse and Antares, but the star at the center of the Crescent Nebula, WR 136, is a lot closer to exploding than either of those red supergiants. The gas you see is the former outer layers of the star, meaning it has already passed through its red supergiant stage. WR 136 is a Wolf-Rayet star, and it is very near the end. Maybe it won't appear in the sky in our lifetimes, but at some point, this star that has already shed its hydrogen envelope will brighten by an enormous factor as its core collapses and blasts the remaining outer layers of the star into space.
Telescope: Celestron Edge HD 925 at f/2.3 with HyperStar
Cameras: RGB shot with an ATik 314L+ from the dark skies of Mt. Pinos
Hα shot with an Atik 414-EX and Atik Hα filter from my light polluted backyard
Preprocessing in Nebulosity; stacking, channel combination, and processing in PixInsight; final touches in Photoshop
The Crescent Nebula (NGC 6888) in RGBHα
I used a stack of 13 4 minute exposures for the RGB component, and a stack of 20 3 minute hydrogen-alpha exposures as an enhancement for the red channel. I'm not sure what I was thinking when I was shooting emission nebulae without the Hα layer - the amount of detail it brings out is pretty incredible.
We're all waiting for the next supernova in the Milky Way. It's been centuries since the last one visible to the naked eye (unless you count 1987A - but that wasn't in the Milky Way). We've all read about Betelgeuse and Antares, but the star at the center of the Crescent Nebula, WR 136, is a lot closer to exploding than either of those red supergiants. The gas you see is the former outer layers of the star, meaning it has already passed through its red supergiant stage. WR 136 is a Wolf-Rayet star, and it is very near the end. Maybe it won't appear in the sky in our lifetimes, but at some point, this star that has already shed its hydrogen envelope will brighten by an enormous factor as its core collapses and blasts the remaining outer layers of the star into space.
Telescope: Celestron Edge HD 925 at f/2.3 with HyperStar
Cameras: RGB shot with an ATik 314L+ from the dark skies of Mt. Pinos
Hα shot with an Atik 414-EX and Atik Hα filter from my light polluted backyard
Preprocessing in Nebulosity; stacking, channel combination, and processing in PixInsight; final touches in Photoshop