|The planetary nebula NGC 246 ("Skull nebula", "Pac-Man nebula") in the constellation Cetus on December 5 / 6, 2015.
The expanding emission nebula ejected from a red giant star at the end of its life is 2000 light-years from Earth and was discovered by Friedrich William Herschel in 1785
Twenty-one exposures of approximately 3 minutes at ISO 800 with no dark frame subtraction were stacked with Deep Sky Stacker
(resulting in a 1 h 10 min exposure) and further processed in Photoshop.
|Equipment: Canon EOS 450D Baader modified camera, TeleVue Paracorr Type II coma corrector,
16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform,
Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison:
image of the moon with the same equipment).