Comets - 48P/Johnson - 0048P
Type Periodic Perihelion Date 12 August 2018 Perihelion Distance (q) 2.0 Aphelion Distance (Q) 5.0 Period (Years)   6.5 Eccentricity (e)   0.43 Inclination (i)   12.2 Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 6 May 2018
E. L. Johnson (Johannesburg, South Africa) discovered this comet with the 25-cm Franklin- Adams Star Camera on 24 August 1949, while making follow-up observations of the new minor planet 1949 OG. He determined the magnitude as 13.8 and described the comet as very small, diffuse, and without a central condensation. He confirmed the comet on 25 August and then found prediscovery images on plates exposed on 15 and 20 August. The comet was already passed its closest approach to Earth when discovered, having passed 1.26 AU away on 3 August. Subsequently, the comet's brightness was virtually unchanged during the coming weeks as it headed for its 16 September perihelion passage. Jacobus Albertus Bruwer (Union Observatory Annexe, Hartbeespoort, South Africa) recovered the comet with the 25-cm Franklin-Adams Star Camera on 6 August 1956. He estimated the magnitude as 13.5. The comet has been seen at every return since its discovery. The perihelion distance of 2.2 to 2.3 AU prevents it from coming closer to 1.2 to 1.3 AU from out planet. Subsequently, the comet never becomes especially brighter and usually experiences a relatively slow brightening and fading as it approaches perihelion. Following the discovery apparition, the comet experienced another very favorable return in 1956 and attained a maximum magnitude of 13 around the time it passed closest to Earth (1.28 AU) on 22 August. Conditions were less favorable in 1963 and the comet's maximum reported magnitude was 17, with the closest approach to Earth being 1.38 AU on 11 September. Still more unfavorable conditions existed during the 1970 return with the closest approach to Earth being 1.65 AU on October 8. The maximum reported magnitude was only 18.8. Date 10x10 mag Error Kphot mag Coma ' 17-Apr-18 16.84 0.04 16.0 0.4 25-Apr-18 16.52 0.03 15.7 0.5