This H-Alpha image shows the Hydrogen Nebulosity near the Monster Star Gamma Cas in Cassiopeia. (40,000 times more luminous than the Sun)
This image is a stack of 100 exposures 15 minutes each through a Ha filter. Esprit 100 refractor+ QHY16200 CCD @ -20C.
(8,11,12 june+ 5,6,9,10,11,12,13,14 november 2017.)
Knight Observatory, Tomar