Two Visible Comets
Predicting comets is rather like predicting the weather - your mileage may vary. However we may have a good chance to see two naked eye comets in the sky during late April and early May this year. Two comets visible to the eye at the same time has not happened since 1911. Both comets were discovered by patrols looking for asteroids which approach the Earth closely LINEAR C/2002 T7 and NEAT C/2001 Q4. LINEAR is the name of a satellite (LIncoln Near Earth Asteroid Recorder) and NEAT is a telescope watch at Palomar (Near Earth Asteroid Tracking). These two powerful telescopic systems are major killjoys. They almost always sight comets long before amateurs can spot them those robbing us poor mortals of the small fame of having a comet named for us.The two comets were expected to reach naked eye brightness by April although LINEAR after a fast start is lagging rather badly. Neither will probably reach anything like the great brightness of historically famed comets but both have a good chance to be about as bright as the North Star Polaris which means among the 60 or so brightest objects in the sky.Comet LINEAR will be in the East near the Great Square of Pegasus (Flying Horse) in April, moving south past Pisces (The Fishes) and Taurus (The Bull) until it gets so low in Cetus (Whale) that it cannot be seen by early May. People south of the Equator will see LINEAR from April until July. LINEAR will be below the crescent Moon on April 15th through 17th as the Moon is rising early in the East. Binoculars should help, but telescopes will be useful only after locating the comet.Comet Neat will appear in the West South West starting near the brilliant star Sirius at the end of April and rapidly moving up the sky past the constellation Monoceros (Unicorn) between Cancer (Crab) and Gemini (Twins) by the end of the third week of May. From Southern Rhode Island a fuzzy ball with possible tails is almost certain to be visible with binoculars during the last week of April and the first three weeks of May. Orion (The Hunter) will be setting and Venus will be in the Northwest during this time. After this time NEAT will begin to turn north and finally cross the Ursa Major (Big Dipper) near the beginning of August.Comets are often called dirty snowballs. As they enter the inner solar system, the Sun begins to heat them to the point where one volatile substance after another begins to evaporate creating a kind of foggy tail that streams away from the Sun. While the tail may look like a rocket exhaust pushing the comet, in fact the Sun's light and solar wind drive the comet's tail away. As the comet heats up more, a second type of tail often appears composed of dusty particles of gritty sand. These stay in the orbit of the comet for many decades. Sometimes a major planet like the earth crosses one of these orbits and encounters the gritty dust particles. Then we have a meteor shower such as we had in November a couple of years ago when Earth crossed the path of Comet Tempel-Tuttle. This was certainly a memorable night. We won't be crossing the path of either of these two comets in our lifetime.Having problems spotting the comets? Well, come down to Frosty Drew Observatory in Ninigret Park any clear Friday night in late April and during May. We'll do our best to sight the two comets, and four planets as well. Quite a show this Spring.