Astro-Physics RH305 f/3.8 STXL-16200 at -20°C 1.1"/pixel (measured) 60 x 2-min 5-nm H-alpha Dark subtraction, astrometric alignment, median stacking, histogram stretch All processing in Maxim DL I'm very happy with the minimal diffraction from the microlenses, really only barely evident on mag 1.7 Alnitak and it's neat to see the the Alnitak C-component at mag 9.6 (nearby star to left of Alnitak, 60" at PA 10°) as well as a mag 14.8 faint star to the right of Alnitak (45" at PA 175°). I see no evidence of the mag 9.6 B-component (2.2" at PA 167°). Throughout the rest of the image, away from Alnitak's glare, there are 16th-mag stars visible in this H-alpha image, which is pretty remarkable for 2-min subs and a 5-nm bandpass! (Is that amp glow in the lower right? The image is rotated 180°, so the artifact was originally at upper left.)
That is a beautiful shot! Love that field. (Could be amp glow, though that would be unusual given proper dark subtraction.)
