M81

Mar 26th, 2020

L: 167min RGB: 40min I added another half hour of luminance and re-processed M81. Total: 2 hours 47 minutes of luminance and 40 minutes per color channel. By the way, here’s a simple example of why astrophotographers chase faster optics, despite the more complex collimation and higher cost (not only for the primary mirror but also for correctors). I calculated how much time it would take for a “typical” f/5 Newtonian to gather the same amount of light. My setup: f/2.9 + Paracorr (1.15) 2.9 × 1.15 = 3.335 3.335 × 3.335 = 11.122225 “Typical” Newtonian: f/5 Using a standard corrector without reducing speed: 5 × 5 = 25 So: 25 / 11.122225 ≈ 2.24775 Considering only luminance, not color: 2 hours 47 minutes = 167 minutes 167 × 2.24775 ≈ 375.37 minutes Result: 2 hours 47 minutes at f/3.335 equals about 6 hours 15 minutes at f/5.

Mar 24th, 2020

Messier 81 (also known as NGC 3031 or Bode's Galaxy) was first discovered by Johann Bode in 1774. Because of this, it is often called Bode's Galaxy. 2 hours of L subs at 60 and 120 seconds each, and 40 minutes each of RGB (subs at 120 seconds).