Masayoshi Ueda

Meteor luminosity at 160 km altitude from TV observations for bright Leonid meteors

Two atmospheric trajectories have been determined by simultaneous observations with image intensifier-fitted TV cameras and conventional photographic cameras for two bright Leonid meteors (fireballs) in 1995 and 1996. Beginning heights recorded by the photographic method are lower than about 130 km, but those observed by the TV systems are closer to 160 km. The primary reason for this difference is the sensitivity of the observing systems. However, the difference in the sensitive wavelengths (up to 900 nm for the TV systems) could be another factor contributing to the large difference between the two methods. This suggests that the beginning heights of high speed bright meteors such as Leonid meteors are much higher than previously thought.

Simultaneous observations of meteors with the radar and TV systems

We have carried out a simultaneous observation of radar and optical meteors with the MU radar (Middle and Upper Atmosphere Radar), Shigaraki and TV camera systems. We usually obtained about 20 meteors per an hour with 85 mm lens, but very small part of them are simultaneously observed by the MU radar (< 5%), suggesting the significance of rectangular scatterring. We have analyzed about 20 simultaneous meteors with magnitudes from 0 to +5.5, most of which are overdense meteors. For Geminid meteors, a linear relation between the logarithm of the echo duration and the absolute magnitude of the TV meteor, was deduced.