Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years.
Imaging telescopes or lenses: Astro-Physics 152mm f/7.5 Starfire EDF
Imaging cameras: FLI ProLine Proline 16803
Mounts: Software Bisque Paramount MX
Guiding telescopes or lenses: Takahashi FS-60C
Guiding cameras: Starlight Xpress Superstar
Focal reducers: Astro-Physics AP 4.0″ Field Flattener
Software: PixInsight 1.8, FocusMax, Maxim DL Pro 5, Software Bisque TheSky6 Professional, Photoshop CS Photo Shop CS5, CCD Autopilot 5
Filters: Astrodon E-series LRGB Ha 5nm
Accessories: Sirius Dome
Dates: Feb. 21, 2014
Locations: Sydney Australia
Frames: 19×1200″
Integration: 6.3 hours
Author: David Nguyen
AstroPhotography of the day by SPONLI 12 Aug 2014