M17, The Swan Nebula


Ron Brecher

Guelph, Ontario, Canada

SBIG STL-11000M camera, Baader Ha, R, G and B filters, 10″ f/6.8 ASA astrograph, Paramount MX. Guided with QHY5 guide camera and 80 mm f/6 Stellar-Vue refractor. Acquisition, guiding and mount control with TheSkyX. Focusing with FocusMax. Automation with CCDCommander. All preprocessing and post-processing in PixInsight. Shot from my SkyShed in Guelph, Ontario. Nearly full Moon for Ha and little moonlight for RGB. Good to excellent transparency and poor to good seeing throughout acquisition.

6x10m R, G and B and 3x20m Ha unbinned frames (total=4 hr).

Complete processing details at astrodoc.ca/m17

Messier 17 is known as the Swan Nebula, owing to it’s appearance in the eyepiece. In a moderately sized telescope, only the brightest part of the nebula can be seen easily, and looks distinctly swan-like. Another nickname is the Omega Nebula; personally I see only a very limited resemblance to that Greek letter. The Swan swims in the Sagittarius Milky Way about 5000-6000 light years away. It is about 15 light years a cross and its total mass is about 800 times that of the Sun. From our vantage point, its location in the sky is not far from the Eagle Nebula.

The above image blends the red, green and blue colour channels with data collected through a deep red H-alpha filter. The black and white image at right shows the H-alpha data on its own. A full size H-alpha image is available by clicking on the image.