The Crescent Nebula (a.k.a. NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It has an interesting history as it formed by fast stellar wind from a star catching up and colliding with slower moving wind ejected by the star when it became a red giant around 250,000 years ago source: wikipedia).
The sky was pretty clear both nights I went out to collect images and I managed to get over two hours on an object. I used my Astronomik UHC Clip filter which is very good for emission nebula with lots of ionized hydrogen especially in light polluted areas. However, this really would have benefited with some 12nm H-alpha filter luminosity frames. Trevor Jones from Astrobackyard did great job recently with this nebula using an H-alpha filter and has commented on this on his website. As I write this tonight, it is clear outside but the moon out making it not a great night for nebula imaging unless, that is, you are using an H-alpha filter as they only let H-alpha light in and block everything else including moonlight. I see one of these filters in the future.
Last thing, I have seen many other images of this and other nebulae where the star fields are quite reduced. I did some reduction in Astronomy Tools with this nebula and could have done more but I actually like the stars so did remove as many as I could have. Hope you enjoy...
https://kurtzeppetello.smugmug.com/
Comments