SUNSET: 
0
Photographer:
Jon Greif
Location of Photo:
Alpine, CA, USA
Date/Time of photo:
August 6-16, 2025, between 9 pm and midnight PDT
Equipment:
TS-Optics 8" f/4 ONTC Newtonian Telescope, 10Micron GM1000HPS Mount, ZWO ASI2600MM Pro camera, ZWO RGB, Ha, Oiii and Sii filters, MoonLite focuser, NINA acquisition software and Pixinsight processing software.
Description:
This is the Crescent Nebula photographed in a background of swirling hydrogen and oxygen gases (the hydrogen gas is red, the oxygen is blue). The Crescent Nebula (also known as NGC 6888) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792. It is formed by fast stellar wind from the Wolf-Rayet star WR 136 colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves. The image represents 21 hours of exposure time over 7 clear nights between August 6 and August 16 through the 8 inch Newtonian telescope in our Backyard Observatory.
