Some excited students called me after midnight wanting to know what the
bright object in the sky was that was flashing different colours. I went out
to have a look, and concluded that the object is Sirius, but there certainly
is something odd about it: it's twinkling very strongly and with the
twinkling come very distinct coloured flashes. All sorts of colours, just
for an instant. The effect is stronger through binoculars. The other
brighter stars are higher up from the horizon, in Orion, and they look
normal. I've tried looking for the same effect in other stars round the same
elevation as Sirius (assuming it is atmospheric) but there's nothing bright
that is not beind a cloud or lost in the sodium haze of Trieste. Is this
effect known to anyone? Ice crystals in the sky or something?
Mark.
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Mark Sylvester
United World College of the Adriatic, Duino, Trieste, Italy.
msylvest@spin.it
tel: +39 40 3739 255
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