SUNSET: 
0
Photographer:
Mike Olason
Location of Photo:
Tucson, Arizona
Date/Time of photo:
2025 Sept 21, 0226UT
Equipment:
91mm f/4.9 Refractor and ASI533mm camera
Description:
Comet C/2025 R2 (SWAN) is still just above the horizon as observed from Tucson when the evening sky gets dark enough to observe the comet in fading twilight above the low atmospheric haze just before the comet sets, on 9/21 UT at 2.5 degrees above the horizon calculated the comet magnitude at 6.8 in a fading twilight sky which only allows one to see a small part of the tail. Yes, Comet C/2025 R2 (SWAN) was previously known as SWAN25B.
