(meteorobs) Bright Fireball over Alberta Dec. 18

[Bruce McCurdy]

    Interesting report from one of this area's most experienced observers of 
an exceptional fireball seen earlier this week.

    Bruce
    *****


----- Original Message ----- 
From: "Noble, Mike" <MNoble at NRCan.gc.ca>
To: "Astronomy Discussion list" <astro at mailman.srv.ualberta.ca>
Sent: Monday, December 18, 2006 9:36 AM
Subject: [Astro] RE: Bright Fireball at 1:13:50am this morning


I tried sending this message at 2:30am this morning, but it doesn't
appear to have made it, so here goes again.

I was returning home from an imaging session at my preferred site NW of
Pigeon Lake early this morning and saw a bright fireball according to my
watch at 1:13:50am and location 53 11 32.14 N 113 59 31.84 W as derived
from Google Earth.  I was between two farms and there was a narrow tree
line along the road on the north side.

I just checked my watch and it is 32 seconds slow so the adjusted time
should read 1:14:22am plus or minus 5 seconds for the shock value at
realizing what just transpired.

I was traveling East on Glen Park Road (Twp Rd 490) at 100kph when I
noted the snow having a bluish-green illumination on either side of the
road.  I blinked and said to myself, "What the..."  High overcast clouds
had rolled in to finish my imaging session and there were some breaks in
the clouds as I drove home but the brightest illuminated cloud area was
just to the immediate north of my position and drew my eyes.  I looked
up through the drivers' side window and could see the terminal end of
the fireball.  The illumination from the fireball lasted for 3 or 4
seconds total but the portion of the fireball that I could see was only
the last second or so.  The fireball looked like a very bright
white-bluish-green flare or star shell that was significantly slowing
down as it plummeted straight down into the atmosphere.  The snow
covered landscape seemed illuminated far brighter than any full moon
night that was absolutely clear.

Another impression was the fireball was coming straight down and that it
passed through the clouds.  The hazy clouds were thin enough though that
this impression could have been mistaken but the illumination from the
fireball allowed me to discern a mottled pattern in the cloud rather
than as an amorphous blob of haze.  Once the fireball fragmented, the
fragments were an orange-red for another 1/4 second as they decelerated.
I estimate I could see the terminal end from around 60 degrees altitude
down to 45 degrees and the fragments dropping another 2 or 3 degrees of
arc from there before the event was finished.  The azimuth of the
fireball looked straight north but maybe leaning a little to west or 355
degrees, but no more than that.

I was wondering if there were any other reports on this sighting.  BTW,
this was the brightest fireball that I have ever seen, by many
magnitudes.

Mike Noble

-----Original Message-----
From: Bruce McCurdy
Sent: Tuesday, December 19, 2006 11:04 PM
To: Astronomy Discussion list
Subject: Re: [Astro] RE: Bright Fireball at 1:13:50am this morning

Interesting report Mike, sounds like a heck of an observation. Do you
even have a ballpark estimate as to magnitude? Half moon? Full Moon? Sun??

I recommend you send a report to the Meteorites and Impacts Advisory
Committee. They want reports of Canadian fireballs. There's an online
report form at http://miac.uqac.ca/MIAC/fireball.htm .

Bruce
*****


----- Original Message ----- 
From: "Noble, Mike" <MNoble at NRCan.gc.ca>
To: "Astronomy Discussion list" <astro at mailman.srv.ualberta.ca>
Sent: Wednesday, December 20, 2006 10:52 AM
Subject: RE: [Astro] RE: Bright Fireball at 1:13:50am this morning


I submitted the observation to AMSMeteor.org and they numbered it as
event 495.  I then realized I should have sent it to our Canadian site
instead.  Because there was no reaction to my submission on our
Discussion List, I checked the Contacts list on the MIAC site and then
emailed Chris Herd and Martin Connors to see if the All Sky Cameras
might have recorded the event.

Martin got back to me and said he would look at the sensor logs and also
forwarded my report to Alan Hildebrand.  Alan in turn, forwarded me &
Doug Hube, Don Halidiuk's mpeg record of the fireball from the MIAC
sensor down in Calgary.  Here's hoping the Northern Alberta Sensors
picked up this burst.  There was over cast clouds, but they were fairly
thin and I could easily see the terminus (last second) of the fireball
through the clouds directly overhead.  I didn't see the 2 or 3 flashes
as shown on the MIAC camera because it was directly above my vehicle and
I don't have a sun roof.  What I did see was the snow covered fields and
clouds lit up brighter than any Full Moon night so my guess was greater
than -13.  I saw the glowing Fireball descending & slowing down and then
finally breaking into several fragments which were reddish-orange and
these continued in a straight path but only lasted over another couple
of degrees of sky before winking out.  Maybe the fragments slowed down
enough and we've got some fragments on the ground West of Edmonton.

I was out imaging from 8pm to 12:40am last night at the Talisman Site
and drove back past my observation site at 1:20am and rechecked my
altitude estimates of the fireball.  I will be contacting all concerned
that we need to revise my altitude estimates down by 5 degrees.  I could
only see 2 or 3 degrees above Polaris from my driver side window which
means my start altitude for the last second of the fall should be 55
degrees, not 60.  As for Azimuth, I now think it should be shifted to  2
to 5 degrees east of north also.  I didn't have Polaris or any other
stars as a reference during the fireball because of the clouds and could
only guess at the azimuth relative to the direction I was driving.

If anybody wants Don's 3mb MIAC file of the fireball, email me at
mnoble at nrcan.gc.ca and I can forward the file to you.

Mike