COMET STREAKS PAST EARTH THIS WEEKEND: Comet 46P/Wirtanen is approaching Earth for an historic encounter on Dec. 16th–one of the 10 closest comet flybys of the Space Age. Where should you look? Face in the same direction as the windmill:
Andy Horstmanshoff took the picture outside Lovelock, Nevada, on Dec. 14th. “Comet 46P/Wirtanen is the green blob in front of the windmill,” he says. “The stars of Orion and Taurus framed the comet beautifully in the crystal clear sky of Nevada’s high desert.”
You might expect such a nearby comet to be very bright. It’s not. 46P/Wirtanen is a small comet and, thus, barely visible to the unaided eye despite its proximity. Rural observers describe it as a faint misty cloud about the size of a full Moon, best seen using averted vision. Urban sky watchers have almost no chance of seeing it through city lights.
It is, nevertheless, an easy target for digital cameras. Even a short exposure reveals the comet’s spherical form and emerald green hue. “My picture is a 20s exposure,” says Horstmanshoff. “I used a Canon 5D MK III camera set at 5000 ISO.”
This weekend, Comet 46P/Wirtanen may be found in the constellation Taurus shooting the gap between the Pleiades and Aldebaran. A good time to look is just before midnight when the Bull is climbing high in the southern sky.