Glowing blue from central star HD200775, the Iris Nebula is categorized as a reflection nebula. Unlike a bright, red emission nebula, which bears ionized gas that produce its own light, a reflection nebula is composed of dust grains that scatter bluer light more efficiently than redder light (similar to why the sky is blue). Astronomers from the early 20th century, such as Vesto Slipher and Edwin Hubble, are credited with developing these nebula classifications, and over a hundred years later we are still using them.

Acquisition Date: June 10-15, 2024

Acquisition Site: San Carlos, CA

Equipment: Takahashi TOA-130NFB, ASI2600MM, Astrodon LRGB filters, Astrodon MOAG, Astro-Physics 1200GTO

Subframes: L 180 x 180s, RGB 172 x 180s

Software: PixInsight, Apple Photos, Sequence Generator Pro, PHD2, APCC, Starry Night, SharpCap