Caption for UK Schmidt image No. 1 of Comet Hyakutake 

This image of Comet Hyakutake B2 1996 was made with the 1.2m UK Schmidt
Telescope at Siding Spring Australia. It is an 18-minute exposure taken in
blue light and shows the early appearance of the ion tail blown off the
comet by radiation from the sun. The 'notch' in the tail is probably due to
a discontinuity in the solar wind. At the time of the photograph the comet
was slightly more distant from the sun than is the earth. The background
stars appear as short trails because the telescope followed the rapid motion of
the comet through the solar system.