Natural N7

George Zhou

Year 12 , Camberwell Grammar School

Comet McNaught

Comet C/2006 P1 McNaught , the Great Comet of 2007, was discovered by Robert McNaught as part the Siding Springs Survey in Australia. The comet brightened in late January and was visible for a prolonged period of time in the Southern Hemisphere; soon it was named the brightest comet for 42 years (since Ikeya Seki 1965). The image shows a series of photos of the comet over a period of four days, presenting the declining brightness and tail length as the Comet McNaught receded from the Earth. The tail of a comet is produced when material ejected from the nucleus is carried away from the comet by the solar wind, the apparent length of which is dependent on the comet’s distance from the Sun and the observer (Earth). Visible also from the photographs is the anti-tail streaming from the coma – a small extension of the tail towards the right of the images. The comet declined in brightness dramatically over the period of 4 days, with an estimated brightness of -2 on Jan 22 and 0 on Jan 25. The photos were taken with a Canon 400D SLR camera at f/200mm, each consists a stack of several raw photos to increase the signal-noise ratio, thus the visibility of the tail section of the comet. At Burwood (VIC), where the photos were taken, the light pollution was severe, thus extremely long exposure shots were not possible and the graceful tail seen in professional shots was not captured.