Telescope: Meade SN8 at f/4, Orion Atlas EQ-G
Camera: ZWO ASI071MC Pro, 10C; Gain: 200
Filter: 2” OPT Triad Ultra Hb, OIII, Ha, SII filter
Guide scope: Williams Optics 50mm, Meade DSI Pro II, PHD
Exposure: 28x240sec saved as FITS
Darks: 32x240sec saved as FITS
Flats: 32x60sec using an LED tracing tablet with 3 layers of muslin
Average Light Pollution: Red zone, Good transparency, first quarter moon
Lensed Sky Quality Meter: 18.8 mag/arc-sec^2
Stacking: Mean with a 2-sigma clip.
White Balance: Nebulosity Automatic
Software: Nebulosity, Deep Sky Stacker, Photoshop
I finally had an opportunity to make a full, uninterrupted run at M27 using my Triad Ultra filter and the results are wonderful! Prior experience with the original Triad showed that it worked very well with H-alpha targets, but struggled a bit with the color of OIII targets like planetary nebula. The Triad Ultra does a much better job, giving high contrast and very nice color. It is really neat to see the outer veil, something that I didn’t know was there before.
The Dumbbell nebula is an expanding shell of gas that was ejected from a sun-like star as it exhausted its hydrogen fuel. Swollen into a red giant, the star shed its outer shell while its core collapsed into a white dwarf. Fierce UV radiation from the collapsed core sets the surrounds gas aglow with the blue/green light of doubly ionized oxygen. The diameter of the nebula is about 1 light-year with an estimated age of 9,800 years. Located between Sagitta and Cygnus, M27 is fairly easy to find with a small telescope. Visually, it shows two lobes connected by a neck of nebulosity, giving the nebula its characteristic dumbbell shape.