| D/1895 Q1 (Swift) | |
| Discoverer: | Lewis A. Swift |
| Discovery Site: | Mount Lowe Obs. |
| Discovery Date: | 24 August 1895 |
| Epoch: | 25 August 1895 (JD 2413430.5) |
| Observation Arc: | 166 days |
| Obs: | 182 |
| Aphelion: | 6.1609 AU |
| Perihelion: | 1.2978 AU |
| Semimajor: | 3.7293 AU |
| Eccentricity: | 0.9725 |
| Period: | 7.2 years |
| Inclination: | 2.9923° |
| Asc Node: | 171.75° |
| Arg Peri: | 167.78° |
| Tjup: | 2.677 |
| Magnitude: | 13.0 (1895 apparition) |
| Last P: | 21 August 1895 (observed) 17 February 2019 (calculated) |
| Next P: | 19 September 2026 (calculated) |
D/1895 Q1 (Swift) is one of 13 comets discovered by American astronomer, Lewis A. Swift. A Jupiter-family comet, it was last seen in February 1896 and was not observed since.
On September 15, 1967, the Mariner 4 spacecraft encountered a dense "meteor storm" that is more intense than anything seen from Earth for 45 minutes, which may have damaged bits of insulation and temporarily changed the attitude of the spacecraft. What caused it remained a mystery until in 2006, astronomer Paul Wiegert examined old comet data and found that Mariner 4 would have been 20e6km from the possibly shattered nucleus of D/1895 Q1 (Swift). However, Wiegert noted that the comet's orbit during its 1895 apparition wasn't precisely known, leading to a large potential error in the comet's expected location in 1967.