ON THE BRIGHTNESS OF COMET P HALLEY IN THE PAST/

This paper deals with the brightness Changes of comet P/Halley in the past. On the basis of the analysis of Sun-Earth-comet configuration at the time of perihelion passage within 30 apparitions of the comet, si nce 240 BC, several groups of apparitions of similar observing geometr y were specified. These groups were analysed with emphasis on brightne ss variations of the comet on different, long time scales. Absolute ma gnitudes and duration of naked-eye visibility both in pre-perihelion a nd post-perihelion periods of the comet are the main criteria for the aim of in this study. Some brightness increase of the comet in 912-122 2 is indicated.