Analysis of the Lyrids' meteor stream structure for long timeslots

Lyrids' structural parameters (luminosity function parameter r of meteors distribution magnitudes, the S parameter distribution of meteoroids in the mass flow, zenithal hour number (ZHR)) are determined by visual observations made in the 1900-2007 interval. The minimal value of S is equal to 1.54 ± 0.02 and corresponds to the Sun longitude 32.19° ± 0.04°. Lyrids' activity profiles as ZHR depending on the Sun longitude (L) were constructed for studying the flow activity. ZHR averaging for the individual values was held according the observation in 1900-1963, 1900-2000, 2001-2007 and 1900-2007. The peak position for all groups is the same within the error and equal to 32.326° ± 0.107. Two periods of Lyrids activity were revealed: a period which is close to 60 years; and s period of about 10-12 years.