McNaught Bags His 50th Comet

Admit it: At one time or another, you've probably wished that you could chance upon an undiscovered comet and have your name forever linked to that cosmic interloper.

McNaught and his telescope
Rob McNaught stands with the 20-inch (0.5-m) Uppsala Schmidt telescope at Siding Spring Observatory.
R. H. McNaught / MSSO
Now imagine that your "eureka moment" has happened not just once but 50 times! With a track record like that, you'd be unique among all cometary observers, past and present. In fact, you'd be Rob McNaught.

McNaught has just discovered his 50th comet. He spotted it, as he does most often these days, on images taken with the 20-inch (0.5-meter) Uppsala Schmidt telescope at Siding Spring Observatory in Australia. The discovery, now known formally as P/2009 Q5, came early on the morning of September 1st in Australia (late on August 31st Universal Time). It appeared as a fuzzy 17th-magnitude blip in a stack of five 30-second exposures taken in northern Cetus after the nearly full Moon had set.

Right now P/2009 Q5 is nearly as close to us as it ever gets in its 18-year-long orbit (the "P" in its designation stands for "periodic"), with perihelion coming up soon on September 20th some 270 million miles (435 million km) from the Sun. Only truly die-hard observers have a chance to photograph it — let alone to see it by eye.

Comet McNaught (C/2009 Q5)
The latest Comet McNaught (C/2009 Q5) isn't much to look at, but it represents a milestone for its discoverer.
R. H. McNaught
But this story is more about perseverance than pizzazz. For more than two decades, month in and month out, McNaught has combed the heavens for small interplanetary visitors that have ventured near the Sun. His first comet find, made with just an 85-mm camera lens, came in 1987. (He also gets shared credit for spotting Comet 1978 XXVII, later redesignated C/1978 G2, but that one came in 1993 as he inspected archival images.)

Since 1987 McNaught has racked up an impressive portfolio that now totals 38 solo comet discoveries (15 of them periodic), 12 shared discoveries, and 410 asteroids. Doing the math, that's 2.3 comets and 19 asteroids per year — apparently, McNaught doesn't sleep much. According to a nifty compilation maintained by German comet enthusiast Maik Meyer, McNaught's closest competitor is Carolyn Shoemaker, with 32 credited discoveries.

Comet McNaught (C/2006 P1)
For a great comet picture like this, all you need is a basic camera with a 50-mm lens, a 50-second exposure, and a great comet! Rob McNaught captured his namesake (C/2006 P1) on January 10, 2007, from Siding Spring Observatory in Australia. Click on the image for a larger view.
R. H. McNaught
(I'd be remiss if I didn't give a nod to those individuals, and particularly to Rainer Kracht in Germany, who have spotted more than 1,600 comets in images from the Solar and Heliospheric Observatory.)

So why is McNaught so successful? Of course, it helps to have the superb skies of Siding Spring Observatory, little competition in the Southern Hemisphere from other would-be comet hunters, and an assignment to survey the sky systematically for near-Earth objects.

His favorite find? "As a spectacle it has to be C/2006 P1," McNaught tells me. But as a discovery it is most certainly the 1987 comet. Amateur discoveries are always more exciting!"

Congratulations on hitting the big Five-Oh, Rob — and keep up the good work!

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