The solstice comes on Wednesday Dec. 21, at 21:48 by Universal time (5 or more hours earlier by North American clocks). This is the middle of north-hemisphere winter, in the sense that the Sun is farthest south and daytime is shortest. Sone call it the beginning winter, since the coldest weather is liable to follow later. Even though from now – comforting thought! – the Sun begins to return a little northward each day.
See the end note about enlarging illustrations.
This scene, for our chosen mid-USA location, is a couple of hours after the exact solstice moment, yet fairly early in the long winter night.
The “antapex of Earth’s motion,” the point we are heading away from in this part of our orbit around the Sun, now coincides almost exactly with the March equinox point, where the ecliptic crosses the celestial equator northward and where the Sun was at the northern spring equinox.
The Sun is 90° to the right from here; and 90° to the left is the other solstice point, where the Sun will be half a year later.
That June solstice point is marked by wonderful deep-sky object, the Messier 35 cluster, about as bright as a 5th-magnitude star (though less easy to see, because its stars are spread over a patch about as large as the Moon).
There is no such skymark for our March equinox point. The left side of the Great Square of Pegasus pointed south to it, but precession has moved it westward. This is in fact quite a good way to visualize precession, which continually slides the celestial equator along in relation to the ecliptic.
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ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor. One way: right-click, and choose “View image” or “Open image in new tab”, then enlarge. Or choose “Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.
Sometimes I make improvements or corrections to a post after publishing it. If you click on the title, rather than on ‘Read more’, I think you are sure to see the latest version. Or you can click ‘Refresh’ to get the latest version.
I’ve recently begun visualizing sidereal time by watching the big clock in the sky. Now I can add visualizing precession. Thanks for all your mental challenges. You are a prodigious teacher.
Calendar Winter begins on the 21st but professional metrologists use the 1st of December.I always say the 21st which also in a way is the beginning of the real New Year.For me way up at about 54.6 North my earliest sunset began on 9th,if I remember correctly, at 15:38 and stayed at that time until the 19th when it moved to 15:39 and on the 22nd it’s 15:40 on so on.If you are into astronomy you notice the increase of light in January but for those who aren’t, sadly most people, they’ll suddenly say in February,”aren’t the days longer now?”