METEORS FROM HALLEY'S COMET: This weekend, Earth is passing through a stream of debris from Halley's Comet, source of the annual eta Aquariid meteor shower. Forecasters expect the shower to peak on May 6-7 with 20 meteors per hour in the northern hemisphere, and twice that number in the southern hemisphere. No matter where you live, the best time to look is during the hours before local sunrise on Monday morning, May 7th. [sky maps]