Our planet rounds out its year –
– but for the next two weeks I shall be in a different part of it (Portugal) and out of touch. So I thought I would give a round-up of events in the sky from now until year’s end. I hope your holiday season is merry and leads into a fine new year, and naturally I hope you have by now received your copy of Astronomical Calendar 2016 and are finding it useful.
First, the Coma Berenicid meteors.
The picture is over-glorified, I’m afraid. You’ll be lucky if you see as many as three an hour in the after-midnight hours of December 16 and perhaps 17. Nothing to the great Geminids of December 13/14 (for which, unfortunately, most of us were clouded out). But I like them because they add a few wisps to Berenice’s hair.
The Moon is at First Quarter on December 18.
It is near the crossing of ecliptic and equator, traditionally still called “the First Point of Aries” though now moved by precession into Pisces.
On December 19 the Sun enters Sagittarius.
This date, which happens this year to be a Saturday, was in ancient Rome the Christmas-like festival of Saturnalia, when masters changed places with servants. (Italians still love festivals. I wonder.)
The winter solstice falls on December 22. at 4:48 by Universal Time. The Sun is three quarters of the way around the sky from the March equinox – from the First Point of Aries – and so at this moment, by the older system that did not take account of the movement of the equinox by precession, the Sun, though still among the stars of Sagittarius, is said to enter the sign Capricorn.
Whatever the geometry, the land feels it. Many a north-side garden, many a wood or lane on the southern face of a valley, takes to wondering whether there ever was a Sun.
On December 23 there descend upon us the Ursids –
– like icicles, we might think, since they come at midwinter and from the constellation of the polar Bear. But like all meteors they shine because they super-heat in our atmosphere; not icicles but firecrackers or candles on a Christmas tree.
Christmas Day in the morning:
Comet Catalina, as we now know, may not be much of a Christmas comet, but there is always hope.
The Moon has been dodging other skymarks rather widely – Castor and Pollux, the Beehive cluster, less widely Regulus – but at the end of the year it slides past Jupiter at less than two degrees. The conjunction happens at 19 Universal Time (7 PM in Britain, 2 PM in eastern America), so it favors another part of the Earth; but the Moon-Jupiter exchange of positions will be a striking sight. At the midnight that begins the last day of 2015, the Moon is bearing down on this second-brightest of planets; it has shot past it, by the midnight that begins 2016.