The Iris Nebula (often called NGC 7023, which is the Open Cluster) is a beautiful reflection nebula in the constellation Cepheus. Discovered by W. Herschel in 1794, the Iris Nebula (LBN 487 / VDB 139) is illuminated by a central hot star, which is 10 times the mass of our sun. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. Central filaments of the reflection nebula glow with a faint reddish photoluminesence as dust grains effectively convert the star's invisible radiation to visible red light.