Another one from Tuesday night’s imaging run. NGC 6888,...

Another one from Tuesday night’s imaging run. NGC 6888, the Crescent Nebula in Ha+OIII. The Crescent is an emission nebula 25 lightyears across, about 5000 lightyears away in the constellation Cygnus. This interesting set of structures with multiple shock waves, including an inner shell of hydrogen surrounded by an expanding envelope of oxygen (the semi-transparent bubbling blue structure) is the result of a collision of the fast-burning Wolf-Rayet star WR136 with a massive red-giant star. Imaging notes: 80 x 300-second subs in Ha and OIII, stacked in DSS. Apertura 800mm f/4 Newtonian OTA, ZWO ASI1600MM-Pro mono camera, Antlia 3nm Ha, OIII filters, ZWO ASI290M OAG, on the Sky-Watcher EQ6R-Pro mount with the ZWO ASIAir Plus controller. More astro stuff here: https://SaltwaterWitch.com