Very bright fireball on Friday, Sept 21.

This text is taken from BAA e-bulletin 698 written by John Mason.

Hundreds of eyewitness reports are coming in of a brilliant fragmenting
fireball, visible at about 22:55 BST (21:55 UT) on Friday, 21st September
2012. This is clearly one of the most dramatic events reported to the BAA
Meteor Section in recent years.

On Friday evening, there was scattered and more continuous cloud cover over
much of South-East England, but the rest of the UK and Ireland were largely
very clear, with transparent starry skies. This, coupled with the fact that
many people were out on a Friday evening and the truly spectacular nature of
the fireball itself, are clearly the main factors in it being reported by so
many thousands of people over such a very wide area. This extends northwards
and westwards from a line roughly linking Norfolk in the East to Devon in
the South-West, with the majority of sightings so far received coming from
Wales, the North-West, Central and North of England, Scotland and much of

When first seen the fireball appeared as a single very brilliant object but
it then fragmented into a very large number of bright secondary fireballs,
all travelling along roughly parallel paths across the sky.

One highly unusual feature of this fireball is the length of time for which
it was visible due to its apparent very slow speed of movement across the
sky.  This has led some people to speculate that the fireball was due to the
re-entry of a large fragment of space debris.  However, there are several
aspects of the event, at this very early phase of the investigation, that do
not appear to fit with this hypothesis and it would be unwise to rule out
other possibilities at this stage.

The undersigned has received many reports of the fireball, but these
extracts from the following two more detailed accounts (which have, of
necessity, been shortened here) give a very good general idea of the nature
of this most unusual event.

From David Stewart, Observing Coordinator of the Irish Astronomical
Association (IAA), observing from Delamont Country Park, one mile south of
Killyleagh in County Down.
"At 22:54 BST, a group of 12 IAA members spotted an amazing group of
fireballs rising from trees at the eastern horizon to the right of Jupiter
as seen from the main car park. It was immediately thought they might be
fireworks but they continued to rise at a steady pace and fan out slightly
as they approached us from distance with their numbers increasing and their
brilliant intensity remaining unchanged. 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 and each left a medium trail as
they travelled almost directly overhead. No noise was heard except for the
excited astronomers. A larger group of 4 or 5 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. We were able to observe the
fireballs for 2mins from the trees in the east to the trees in western
horizon and we had particularly good views in that direction. As the
fireballs approached the western horizon their numbers dwindled, possibly
due to burning up and atmospheric extinction, at least 2 or 3 were seen
disappearing behind trees. They were travelling at a speed somewhat faster
than the ISS but not as fast as a typical meteorite on entry into the
Earth's atmosphere."

And from Paul Buglass, reporting on behalf of 10+ members of the York
Astronomical Society (YAS) who were observing at the YAS Observatory, 4
miles west of York. Conditions were totally clear, and a very transparent
"At approximately 10:56ish (BST), a group of us were talking outside
and I noticed a very bright light low down over York (due East) . very
bright with a slight green tint.. It seemed to be moving very slowly,
flickering slightly, and at first I thought it was a low flying aircraft .
then I thought perhaps it was a helicopter.  It still hadn't moved much, but
as the seconds ticked by it slowly started to show more movement to the left
and slightly gain elevation .As its angular velocity increased, the bright
green light started to show a slight tail as it passed through the bottom of
Auriga, and then as its apparent angular speed increased more, a longer
trail of darker red/orange trail formed, with bits coming off, as it
approached the Plough. It then started to lose more distinct fragments
downstream, with a orange almost ember like appearance, then the main bright
white/green head puffed explosively and lost many more orange fragments
which trailed off downstream as it passed through the Plough.. It continued
West in a very flat trajectory, gradually losing the bright head as it moved
to the West, and . faded to about 6 or 7 glowing orange points .  The
direction it was finally lost from view was directly under Hercules.. Total
observation time was possibly 60+ seconds from first sighting low in the
East to fading from view in the West."

Most of the reports received so far are either quite brief or contain a lot
of descriptive information about the fireball's changing visual appearance,
BUT we urgently need more positional information relating to the fireball's
trajectory across the night sky.  Photographs which show background stars,
and even video clips or still images from mobile phones could prove very
useful in this regard.

PLEASE could local society secretaries or other officers who receive this
e-bulletin circulate it to all of their members and any other interested

Clearly this was a very major fireball event and any BAA members who saw it,
or who may have been contacted by non-astronomers who witnessed it, are
asked to collect as much information about the sighting as possible and send
it either to the Meteor Section Director at or to

Useful information will include the name and location of the observer, the
precise time of the event, the altitude and azimuth of the start and end
points of the visible track, the position of the observed track against the
background stars, and a description of the fireball's visual appearance,
colour, etc. together with any unusual features.

This e-bulletin issued by:
John W. Mason, Director, BAA Meteor Section
2012 September 22

The British Astronomical Association supports amateur astronomers around the UK and the rest of the world. Find out more about the BAA or join us.