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Quadrantids(kwod-ran -tidz) A major meteor shower, radiant: RA 232°, dec +50°, that maximizes on Jan. 3 when the Sun's longitude is 282.8°. The zenithal hourly rate (ZHR) at maximum is about 90 and is constant from year to year. The meteoroid stream is narrow, the ZHR being greater than half maximum for only 17 hours: the stream's cross-sectional diameter is about 1.7 million km compared with 20 million and 13 million km for those of the Perseids and Geminids. The stream has its ascending node close to the orbit of Jupiter. Owing to gravitational and radiational perturbations the large ‘visual’ meteoroids are in a slightly different orbit to the smaller ‘radio’ meteoroids. The shower is thought to be associated with comet Machholz. It is named after the obsolete constellation Quadrans Murali found in early 19th-century star atlases. The radiant is actually in Boötes.
a meteor shower with a radiant on the boundary between the constellations Bootes and Draco (on star maps in the early 19th century this region was designated by the constellation Qudrans Muralis). The Quadrantids have been known since 1839. They are observed annually at the end of December and in the beginning of January; on January 3–4, the earth passes through the dense central concentration of the Quadrantid meteor swarm in less than 24 hr. The Quadrantid meteor shower is one of the more active showers.