For every taste and budget, a paperback

The Comet is Coming: The Feverish Legacy of Mr. Halley, by Nigel Calder. New York: Penguin Books. 160 pp. $5.95.

This entertaining, lively, imaginative book could also be subtitled ''the feverish account of Mr. Calder.'' The eminent British science writer has done his usual competent literary job. It is somewhat marred, however, by a needless harping on the perils and foibles of humanity's age-old cometary superstitions.The famous comet returns about once in 75 years. It's a spectacular ''naked eye'' object, as astronomers say, that has awed people for centuries. Calder recounts this history, briefs us on what is now known about comets generally, and gives us something intriguing to ponder in modern scientific speculations about cometary portents.