The Pleadies. The classic “open cluster” example. The group of brilliant, hot “O” type stars has encountered a large region of dust in its travel’s around the galaxy, and their star light is reflecting off the nebulosity. Note the striations, and brush like features near the the brighter stars caused by a “play of light” effect.
Takahashi CCA-250 Astrograph telescope with an ST11000 camera, and Astrodon filters. F/3.6 LRGB (21/7min L, 9/5min each 2×2 RGB).