NGC6888 "Crescent" or "Medusa" nebula. 19.5 hours of exposition
NGC6888 "Crescent" Nebula. Supernova explosion remnants, among Milky Way stars in the background.
Image was taken during 13 observing nights in March/April 2009.
Canon 350Da(baader filter mod), 10" 1:4.7 Newton (F=1200mm)
EQ6PRO SynScan mount, 75mm refractor + QHY6 CCD as a guider
9 hours in H-alpha (Astrodon 6nm), 10 and 20 min. subexpositions mixed. ISO800
10 hours in O-III (Baader 8nm), 20min subexpositions, ISO800
34x2min @ISO200 unfiltered RGB for color stars field and "pseudo-continuum" substraction.
Light-polluted urban sky. About 4.0m visual limit. About 30% of h-alpha frames (10min subexposures) taken under the Moon.