Date Taken: 09/20/2014
Location: Adelaide, Australia
Other Telescope: SW120 f/5 achromat
Mount: AZ-EQ6
Camera: Orion StarShoot G3 Deep Space Monochrome Imaging Camera
Other Camera: ZWO ASI120MM-S guide camera
Processing: Startools, Nebulosity, Deepskystacker
Exposure: 18x1200 sec Ha, 18x960 sec OIII, RGB stars
Other Equipment Used: Tele Vue 0.8x FF/FR, Orion Thin Off-Axis Guider for Astrophotography
Notes: NGC 246, "The Skull", is a eerie-looking planetary nebula in the constellation Cetus, about 1600 light years distant. It has an angular diameter of 4.5'. The central white dwarf part of a binary was mag 9 in 1930 but has since dimmed to mag 12. The complex braided structure is a result of shock waves as the dying star expelled its outer layers. The image was captured in narrowband from suburban Adelaide, using an Skywatcher 120 mm achromat refractor at f/4, mounted on an AZ-EQ6. This telescope is excellent for narrowband work as it has a decent aperture, fast focal ratio, and under these conditions, doesn't suffer from CA. The CCD camera was an Orion StarShoot G3 mono dithered and drizzled, guided with PHD2 using a thin OAG and an ASI120MM-S guide camera. The image is composed of the following: Ha = 18 x 20 min OIII = 18 x 16 min R, G