Fitting for a Friday the 13th is this image of Comet Swan by skywatcher Tony Cook.

Comets were once heralded as omens of impending peril, though if you’re looking out for Comet Swan you’ll need to bring your own luck and – of course – telescope.

The comet is not visible to the unaided eye, but can be found by following the curve of the Big Dipper constellation’s handle.

Cook, who lives just outside of Leeds in the U.K., awoke at 3:00 a.m. British Summer Time on Sept. 30 for some early-morning observations of Swan using an eight-inch Dobsonian telescope and a Televue 85 camera.

“I found it very easily in binoculars, low on the northeast horizon,” Cook wrote in his log. “It’s bright as most comets go.”

Then Cook turned his telescope on the icy sky wanderer.

“Wow! It was bright enough to see that the coma was pale green,” Cook recalled. “Well worth getting up for.”

The result is this four-minute exposure of Comet Swan taken by Cook.

Also known as C/2006 M4, Comet Swan’s orbit can be seen here via NASA’s Jet Propulsion Laboratory’s Small-Body Database Browser. The comet can be found in the northwest after sunset.

-- Tariq Malik

Credit: Tony Cook.