Lucie Green Lecture 17th October
EXTRAORDINARY FIREBALL BURST SEEN BY IAA
OBSERVERS AT DELAMONT COUNTRY PARK
It was immediately thought
they might be fireworks but they continued to rise
vertically at a steady pace and fan out slightly as they
approached us from distance, with their numbers
increasing and their brilliant intensity remaining
unchanged. The trail was between 3 and 4 degrees wide
and 50 to 80 degrees long at zenith. We estimated
approximately 20-30 fireballs were seen following the
same east to west trajectory each with an estimated
brightness between mag. -5 to -7 depending on size, and
each left a small/medium trail as they travelled almost
The path of the fireballs
was observed to the right of Aldebaran and M45 and
rising vertically straight up past Alpha and Beta Cass'.
At their highest point, they were some 5-8 degrees off
vertical toward the eastern horizon. A group of 4 or 5
larger fireballs were at the front of the group and
differences in size were apparent but each burned with a
similar brightness and a distinct orange hue. After the
fireballs passed the top of the summer triangle, 2 or
possibly 3 sonic booms were heard before they passed to
the left of the keystone of Hercules and set behind
trees at approx 1 mile distance at 5 degrees above the
We were able to observe the
fireballs for approx’ 1min 30 sec to 2mins from the
trees in the east to the trees in western horizon as we
had particularly good views in that direction. As the
fireballs approached the western horizon their
brightness began to fade and their numbers dwindled,
possibly due to burning up and/or atmospheric
extinction, at least 2 or 3 were seen disappearing
behind trees at mag.+1 or +2.
They were travelling at a
speed somewhat faster than the ISS but perhaps not as
fast as a typical meteorite on entry into the earths
atmosphere. Their speed remained constant throughout.
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Dr Peter Gallagher Lecture 3rd October
Dave Grennan - 2nd Supernova Discovery
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