The Double Comet Show of 2004

cometComets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) were discovered in August 2001 and October 2002, respectively, by the automated sky-survey programs for which they’re named: Near-Earth Asteroid Tracking (NEAT) and Lincoln Laboratory Near Earth Asteroid Research (LINEAR). Amateurs have been tracking the comets for more than a year as they’ve been approaching the inner solar system and gradually brightening. How bright will they get? With a little luck, one or both could become distinctly visible to the naked eye. Or they could remain targets only for binocular users who know just where to look.

Predicting the brightness of “new” comets — those freshly arrived from the outermost reaches of the solar system, like these — is fraught with risk. Some such comets in recent years have broken up and dissipated completely as they neared the Sun, the most recent being C/2002 O7 (LINEAR). Others suddenly ebbed in their brightening after a promising start; famous cases are comets Kohoutek in 1973-74 and Austin in 1990, both of which were supposed to become bright to the naked eye but ended up only 3rd or 4th magnitude when easily visible, much to the world’s disappointment. However, as of late April both comets were brightening as predicted in this article; they should be nicely visible to observers in both hemispheres during the upcoming months.

The Double Comet Show of 2004

By Greg Bryant, John E. Bortle, and Alan M. MacRobert
© 2004 Sky and Telescope

Image: This 2-image mosaic of Comet C/2002 T7 was acquired by Gianluca Masi and Franco Mallia on April 17, 2004, using the 14-inch SoTIE telescope in Las Campanas (Chile). LINEAR’s short antitail is clearly visible. Courtesy Gianluca Masi and Franco Mallia, Campo Catino Observatory.

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