Meteor creates sonic boom over Canberra on Friday night

[gary]

Elliot Williams reports in the Canberra Times on the meteor that created a sonic
boom over Canberra on Friday night of Dec 22 2017.

Originally Posted by Elliot Williams

Conversation about the meteor turned to Facebook with people as far as Yass, Boorowa and Tumut reporting being able to see the event. Mr Tucker said it would have spanned anywhere between 100 and 250 kilometres.

Full story here :-
http://www.canberratimes.com.au/act-...23-h09pjc.html

[strongmanmike (Michael)]

Dang!..we decide to go to Sydney on Fri, a day earlier than originally planned.. anyone see it?

Mike

[Kunama]

I missed seeing this as I was looking through my scope at the time at M45.
My view went very light and I immediate turned to tell Phil to turn off his head torch.
On turning I could see the area lit up and actually Phil's shadow cast by the meteor.
Both Joe and Phil viewed it and saw it throwing off sparks and a smoke trail..... the sonic boom was about 2 or 3 minutes later....

[LewisM]

Heard it..and thankfully was taking out the trash, so saw SOME of it.

At firsst I thought it was the grunts from ADFA/Duntroon throwing grenades and mortars in our backyard, but figured it out pretty quick.

[OzEclipse (Joe Cali)]

The fireball was bright bluish green at the edges, brilliant white at the core throwing off red projectiles orthogonal to the path. I first caught sight of it just past the zenith heading to the WSW. It cast a light and shadow on the ground approaching but not quite as bright as a full moon. None of us thought to start a timer but when we heard the sonic boom, we mutually agreed it was 2-3 minutes after the visible burn up. 3 minutes equates to 90km

Spectacular. Last one I saw anything like that bright was in 1983 when observing at Arthur Page's Mt Tamborine observatory one night. It lit up the inside of the dome but Arthur couldn't see what had done it. Arthur was doing a photometry run in the observatory. When it hit, he yelled at me thinking I'd turned on the outdoor floodlights.

Joe

[SimmoW (SIMON)]

Kewl!! and Velly Jelly

[LewisM]

Originally Posted by OzEclipse

...the sonic boom, we mutually agreed it was 2-3 minutes after the visible burn up. 3 minutes equates to 90km



Joe

Are you sure on that math Joe?

I get roughly 200,000ft / 61km altitude. Using a mean speed of sound of 661.06 knots / 343 m/s (taking into account temperature RISE above the stratopause in the mesosphere, and temperature drop in the stratosphere).

That's a vertical distance, ignoring slant range, which simply complicates things WAY too much as it introduced many more variables.

[csb (Craig)]

Fortunate fellows!

Actually I'm surprised how many members saw it.

[OzEclipse (Joe Cali)]

Originally Posted by LewisM

Are you sure on that math Joe?

I get roughly 200,000ft / 61km altitude. Using a mean speed of sound of 661.06 knots / 343 m/s (taking into account temperature RISE above the stratopause in the mesosphere, and temperature drop in the stratosphere).

That's a vertical distance, ignoring slant range, which simply complicates things WAY too much as it introduced many more variables.

Your calc is correct Lewis. 90km was just a rough estimate I did in my head while standing at the telescope. Should have checked before posting.


Joe