On March 21st, Comet 252P/LINEAR will make a close approach to Earth--only 0.036 AU (5.4 million km) away. This is the fifth closest cometary approach on record and, as a result, the normally dim comet could become an easy target for backyard telescopes. In fact, it is brightening much faster than expected: data. "Comet 252P/LINEAR has surpassed expectations and is now bordering on naked eye visibility for southern observers," reports Michael Mattiazzo of Swan Hill, Victoria, Australia, who took this picture on March 13th: Comet 252P LINEAR has surpassed expectations by showing a remarkable rate of brightening, about 0.5 magnitudes per day, over the period May 7 to 14 and is now bordering on naked eye visibility for southern observers. The very large, diffuse coma is expanding rapidly, from 10 arcminutes on March 7 to 35 arcminutes on March 14. It may reach 1 degree across at closest approach on March 21. A dark southern sky and a good pair of binoculars is essential. "Since March 7th,