C/2006 P1

C/2006 P1 (McNaught)
Comet McNaught as seen from Swift's Creek, Victoria on 23 January 2007
Discovery date7 August 2006
Epoch2454113.2961 (20 January 2007)
Aphelion~4100 AU[a]
69,480 AU incoming
Perihelion0.17075400 AU
25,544,000 km
Semi-major axis~2050 AU[a]
34,740 AU incoming
Eccentricity1.000019[1] (hyperbolic trajectory)
Orbital period~92,600 yr[2][a]
6,500,000 incoming
Last perihelion12 January 2007[1]
Next perihelionunknown

Comet McNaught, also known as the Great Comet of 2007 and given the designation C/2006 P1, is a non-periodic comet discovered on 7 August 2006 by British-Australian astronomer Robert H. McNaught using the Uppsala Southern Schmidt Telescope.[3] It was the brightest comet in over 40 years, and was easily visible to the naked eye for observers in the Southern Hemisphere in January and February 2007.

With an estimated peak magnitude of −5.5, the comet was the second-brightest since 1935.[4] Around perihelion on 12 January, it was visible worldwide in broad daylight. Its tail measured an estimated 35 degrees in length at its peak.[5]

The brightness of C/2006 P1 near perihelion was enhanced by forward scattering.[6]


McNaught discovered the comet in a CCD image on 7 August 2006 during the course of routine observations for the Siding Spring Survey, which searched for Near-Earth Objects that might represent a collision threat to Earth. The comet was discovered in Ophiuchus, shining very dimly at a magnitude of about +17. From August through November 2006, the comet was imaged and tracked as it moved through Ophiuchus and Scorpius, brightening as high as magnitude +9, still too dim to be seen with the unaided eye.[5] Then, for most of December, the comet was lost in the glare of the Sun.[citation needed]

Upon recovery, it became apparent that the comet was brightening very fast, reaching naked-eye visibility in early January 2007. It was visible to northern hemisphere observers, in Sagittarius and surrounding constellations, until about 13 January. Perihelion was 12 January at a distance of 0.17 AU. This was close enough to the Sun to be observed by the space-based Solar and Heliospheric Observatory (SOHO).[7] The comet entered SOHO's LASCO C3 camera's field of view on 12 January,[7] and was viewable on the web in near real-time. The comet left SOHO's field of view on 16 January.[7] Due to its proximity to the Sun, the Northern Hemisphere ground-based viewers had a short window for viewing, and the comet could be spotted only during bright twilight.[citation needed]

As it reached perihelion on 12 January, it became the brightest comet since Comet Ikeya–Seki in 1965.[4] The comet was dubbed the Great Comet of 2007 by Space.com.[8] On 13 and 14 January 2007, the comet attained an estimated maximum apparent magnitude of −5.5.[9]

The comet was visible in daylight about 5°–10° southeast of the Sun from 12 to 14 January, with a peak brightness of magnitude −5.5.[10] Perigee (closest approach to the Earth) was 15 January 2007, at a distance of 0.82 AU.[11]

After passing the Sun, McNaught became visible in the Southern Hemisphere. In Australia, according to Siding Spring Observatory at Coonabarabran, where the comet was discovered, it was to have reached its theoretical peak in brightness on Sunday 14 January just after sunset,[12] when it would have been visible for 23 minutes. On 15 January the comet was observed at Perth Observatory with an estimated apparent magnitude of −4.0.[citation needed]

Other Languages
Afrikaans: Komeet McNaught
Ελληνικά: C/2006 P1
español: Cometa McNaught
Esperanto: C/2006 P1
한국어: 맥노트 혜성
hrvatski: Komet McNaught
Bahasa Indonesia: Komet McNaught
latviešu: C/2006 P1
Lëtzebuergesch: C/2006 P1 (McNaught)
lietuvių: Maknauto kometa
Nederlands: Komeet McNaught
norsk: McNaught
português: Cometa McNaught
română: Cometa McNaught
shqip: C/2006 P1
sicilianu: Cumeta McNaught
slovenčina: C/2006 P1
slovenščina: Komet McNaught
suomi: C/2006 P1
Tiếng Việt: C/2006 P1