Comet 252P/LINEAR brightened suddenly a few weeks ago, making it 100 times brighter than expected, resulting in viewing opportunities this week for the Northern Hemisphere, starting today. The comet was visible with the naked eye in the Southern Hemisphere last week. In the Northern Hemisphere binoculars will most likely be needed, but viewing is possible.
Kelly Beatty, Senior Editor of Sky & Telescope, said “Don’t expect Comet LINEAR to be obvious with a long tail. Its light isn’t concentrated in a single point but instead is spread out in a soft round glow, larger than the Moon but many thousands of times dimmer.”
Astronomers are not sure how long LINEAR will be visible. It made its closest pass to Earth on March 21, and is now moving away. The best time to view it is about 90 minutes before the sun rises. It will be low in the southern sky, moving quickly north above the tail of the Scorpio constellation. It should be moving between Sagittarius and Scorpius.
Viewers may also want to triangulate the comet’s location with the planets Saturn and Mars, along with the star Antares. On March 31 the comet will be seen climbing to the left of the trio of bodies, roughly along a line connecting Saturn and Antares.
LINEAR’s green color is due to its chemical composition, which is less common than the usual white. When looking for the comet, look for green, not white.
The comet is small – only about 1 kilometer in diameter. It is only visible because it happens to be passing close to earth, and because it has brightened so much. Even so, it will be difficult to spot with the naked eye, especially with the brightness of the Moon this week. Binoculars or a small telescope will help, as will moving to a dark location away from neighborhood and city lights.