SUNSET: 
0
Photographer:
Jon Greif
Location of Photo:
La Jolla, CA, USA
Date/Time of photo:
September 21, 2021, at 11:00 PM PDT
Equipment:
8 inch (2000 mm) SCT with 0.68 focal reducer and ZWO ASI533MC Pro OSC, Rainbow Astro RST 135 mount, 300 mm guide scope and QHY IL5ii guide camera, Ekos capture software on a Raspberry Pi4B computer, Pixinsight 1.8.8-9 processing software.
Description:
Here's an image from a night when the moon was full and the neighborhood lit (Bortle 8 urban backyard). NGC 6774 is a dispersed star cluster in the Milky Way galaxy. It is about 1,000 light years away, which is close to Earth in comparison with other such clusters. In late summer, in a dark night sky, it can be seen with binoculars in the constellation of Sagittarius. The stars, bound by gravity, are about 2.5 to 3.25 billion years old. The cluster, discovered in 1830 by John Herschel, was sometimes thought to be an asterism (a random collection of stars) due to its sparseness and location against the background of the richest part of the Milky Way, and also since the brightest stars in this old cluster perished long ago. In 1966 the Czech astronomer Jaroslav Ruprecht classified it as an open cluster (Ruprecht 147). It received otherwise little attention until 2012, when it was identified as a potentially important reference gauge for stellar and Galactic astrophysics research, particularly the research of Sun-like stars.
