Sharpless 2-73 (also known as LBN 105) was originally thought to be a reflection nebula. However, since there is no nearby hot star illuminating it, it’s now classified (by Steve Mandel) as a type of reflection nebula known as an integrated flux nebula, which is illuminated by light from the entire galaxy.

Technical Information       
Date:               May, 2014
Location:         Green Valley, Arizona
Telescope:      Takahashi FSQ-106EDX
Camera:          SBIG STT-8300M
Filters:             Astrodon Gen 2
Mount:             AstroPhysics 1200
Exposure:        LRGB = 11:2:2:2 hours respectively, all unbinned
Software:         Acquisition: Maxim DL 5, TheSkyX, Pinpoint, CCD Commander
                        Processing: CCDStack, Pixinsight, PhotoShop CS6 with various plugins