153P/Ikeya–Zhang

[3] On 1 February 2002, Chinese astronomer Zhang Daqing from Kaifeng discovered a new comet in the constellation Cetus, and reported it to the IAU.

The comet was observed in 1661, 341 years earlier, by Polish astronomer Johannes Hevelius.

[a] The comet passed perihelion on 18 March 2002, and with apparent magnitude 2.9.

With a multi-hundred year orbit involving asymmetric outgassing the next perihelion passage is expected between 2362–2363.

This data suggested the comet tail had a length greater than 7.5 AU (1.12 billion km), making it the longest yet detected.

The orbital paths of three comets, outlined in turquoise, against the orbits of Jupiter, Saturn, Uranus and Neptune, outlined in green
The orbits of three periodic comets , Halley , Borrelly and Ikeya–Zhang, set against the orbits of the outer planets . Ikeya–Zhang is to the right.