45P/Honda–Mrkos–Pajdušáková is a short-period comet discovered by Minoru Honda December 3, 1948. The comet is named after Minoru Honda, Antonín Mrkos, and Ľudmila Pajdušáková. The comet is on an elliptical orbit with a period of 5.25 years. The comet nucleus is estimated to be 0.5-1.6 kilometers in diameter. During the 2011 perihelion passage the comet was recovered on 5 June 2011 at apparent magnitude 21. On 8 July 2011 the comet had a magnitude of approximately 18, and as of 22 July 2011 the comet's nuclear condensation had a magnitude of approximately 16. The comet is expected to reach a peak magnitude of around 7.3 in late September when it is near perihelion.
The comet made a close approach of only 0.0600 AU (8,980,000 km; 5,580,000 mi) from the Earth on August 15, 2011, and was studied by the Goldstone Deep Space Network on August 19 and 20. Goldstone radar observations on 2011 August 19 and 20 detected echoes from the nucleus and coma. This is only the fifteenth comet that has been detected with radar. The comet will also pass close to Earth on February 11, 2017.
During the 1995 perihelion passage the comet was visible to Solar and Heliospheric Observatory (SOHO) on January 16, 1996 when the comet was around apparent magnitude 7 and 4.3° from the Sun.