M20 - Trifid Nebula
The Trifid Nebula is an "H II region" -- a cloud of hydrogen gas where new stars are being formed. The new stars are hot, therefore blue, emitting ultraviolet light that ionizes the hydrogen gas. The red portion of the nebula is glow from this ionized gas. The blue portion is where star light is being reflected by gas and dust. The dark streaks within the red area are dust lanes that block the light. Thus the Trifid Nebula is a combination of emission, reflection, and dark nebulae, plus an open cluster of stars. It is about 5000 light years from Earth.
5min exposures: 2 R, 3 G, 2 B, 2 H-alpha, 3 OIII, 1 S, 3 luminosity
SBIG ST-8300M cooled CCD camera
Orion 8" F/3.9 Newtonian with Baader coma corrector
Shot and processed with Nebulosity
Shot June 20, 2017, Santa Cruz Mountains, California
