This is is an image from data provided by a friend. He imaged this in 2022 and recently made the last few years of data available to me. I’ve imaged the Crescent twice, in 2021, and 2019. This one shows more detail but some, perhaps all of that is due to better image processing tools.

The Crescent Nebula doesn’t look much like a crescent in this image but in broadband images and through the eyepiece, it gives a much stronger resemblance to its name. This is an HOO image. Oxygen in green and blue and hydrogen in red. This approximates the real colors though not the real proportions.

The nebula is about 5,000 light years away and because it is in Cygnus and the Milky Way runs through Cygnus, there is a strong background of gas and dust.

The Crescent is one of the best examples of a Wolf-Rayet bubble. At the center of that bubble is a large, hot star. At an earlier point in its life the star was sending out a stellar wind that was going at a slower velocity. More recently the star has become hotter and is sending out a faster stellar wind. Where the faster wind catches up to and collees with the slower wind creates a shockwave bubble. It’s a spectacular sight but probably not a very healthy one to be near.

This is 48 hours of HOO data. For all the technical details, see astrobin.