Triangulum’s Pinwheel Galaxy by Oleg Bouevitch
Triangulum’s Pinwheel Galaxy. (Oleg Bouevitch)
Triangulum’s Pinwheel Galaxy by Oleg Bouevitch

The Pinwheel Galaxy in full splendour, its delicate arms dotted with clouds of hydrogen gas.

Photo of the Week for November 2, 2018

Triangulum’s Pinwheel Galaxy by Oleg Bouevitch
Triangulum’s Pinwheel Galaxy. (Oleg Bouevitch

The Pinwheel Galaxy, also known as M33, is nicely positioned high in the east on autumn evenings. At magnitude 5.7, M33 is reasonably bright, but its light is spread over a large area, so it seems much dimmer in a telescope. The ghostly object is difficult to locate in a light-polluted sky even with a big scope. However, in ideal conditions far from town, M33 can be glimpsed with the naked eye. This wonderfully detailed photo shows the galactic Pinwheel in its full splendour—complete with delicate spiral arms dotted with red clouds of glowing hydrogen gas. The largest and brightest of these nebulas is catalogued as NGC604 (in the upper-right part of the galaxy)) and is visible in modest telescopes.

To capture this Pinwheel portrait, Nepean, Ontario, imager Oleg Bouevitch used a Celestron Edge HD 11 flat-field Schmidt-Cassegrain telescope (with a 0.7× reducer for an effective focal ratio of f/7) and a FLI ML16200 monochromatic CCD camera to acquire more than 7 hours exposure, including 280 minutes of luminance data and a total of 150 minutes shot through red, green and blue filters.