Karratha?! I was south of Perth - maybe it was the same ones! I went to call the observatory, so I dialed the operator (remember operators?) and she said "You saw the lights too? If you find out what they are, call me back!"... I never got through to anyone though and just let it go.

It would be interesting if it was the same event. Though unlike the formation you showed, I recall the three stars initially coming together from different locations in the sky to form the triangle - they weren't initially in formation. They stayed in formation then for a few minutes, before disappearing