79P/du Toit–Hartley

79P/du Toit–Hartley or du Toit 2 is a periodic comet, now divided into two parts, in the Solar System with an orbital period of 5.06 years. It next comes to perihelion in September 2023 but is only expected to reach about apparent magnitude 18. It will be less than 90 degrees from the Sun from February 2023 until June 2024. On 26 May 2024 it will be 2.7 AU from the Sun and Earth.

It was originally discovered by Daniel du Toit at the Boyden Observatory, Bloemfontein, South Africa (then administered by Harvard College) on 9 April 1945 with a brightness of apparent magnitude 10.

Uncertainties in the calculation of the orbit meant the comet was lost until rediscovered by Malcolm Hartley of the UK Schmidt Telescope Unit, Siding Spring, Australia in 1982, when it was found to have broken into two parts, probably in 1976. Both parts had a brightness of magnitude 17. Observed in 1987, it was missed in 1992 but rediscovered by astronomers at Los Molinos Observatory, Uruguay on 4 March 2003 at magnitude 17. Fragment 79P-B is lost as it only has a 23-day observation arc from 1982.