Radiant ephemeris and radiant area of the Perseid meteoroid stream

More than 600 double-station photographic recordings of Perseid meteor trails have been obtained at various stations in the period 1937–1985. This large data sample has recently been used to determine the activity profile and mean orbit of the Perseid meteoroid stream (Lindblad and Poruban, 1994). In the present paper the radiant of the Perseid meteoroid stream is studied based on a sample of 592 double-station photographic recordings. The daily motion of the radiant and the change of the size of the radiant area with date is investigated. A daily motion of 1.40° in right ascension and 0.20° in declination is derived. These values are slightly larger than those previously found by other researchers. The contraction of the radiant area at shower maximum previously reported from visual observations is confirmed. In a further study radiant areas derived for the dates of the new and the old Perseid maxima are compared. It is found that the radiant area of the new maximum is smaller than that of the old maximum.