Halley’s Comet

Press, 6 December 1985, Page 14

Halley’s Comet

This chart, drawn by Mr George Patterson, a member of the Canterbury Astronomical Society, plots the times Halley’s Comet will be visible in the night sky. During the dates shown, the comet will rise in the eastern quarter and climb northwards into the sky to set in the western quarter. From April 2 it will climb almost overhead before starting to set. To use the chart, select a date (say April 2) and read

from the bottom. The son will set at 6.15 p.m. and will be 12 deg. below the horizon

by 7.20 pan. Comet Halley will rise just after 9 pan. but will probably be too low to be seen. By 9.50 p.m. the comet will be 10 deg. above the horizon and continue to rise until it reaches its highest point that night at 5 am. By this time the sun will be 12 deg. below the horizon and the sky will be brightening. The sun will rise about 6 JO a.m. The times of full and new moons are plotted along the top. Immediately, below the moons are figures giving

the comet’s total magnitude or brightness—the lower the figure, the brighter the comet

The figures increase slightly from the beginning of the chart as Comet Halley moves away from the Sun. They begin decreasing from March 22 as the comet comes closer to the Earth, the full moon having little

effect on its brightness. The figures drop to 3.9 near the new moon of April 9 and the comet’s closest approach to Earth, then climb rapidly as Comet Halley speeds into deep space. The dotted line marked as the comet’s highest altitude is when it has climbed to within 5 deg. of being directly overhead.