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Tonight

Happy December solstice, everyone

View larger. | This is a a solargraph, created by a simple pinhole camera (made of a beer can!) between June 21 and December 20, 2012. The camera was fixed to a single spot for the entire exposure time, and it continuously recorded the sun’s path as a glowing trail burned into the photosensitive paper inside of it. The breaks and gaps between the lines are caused by clouds. Created by Attila Kalman in Littlehampton, UK.

On the December solstice solstice, we celebrate the (unofficial) first day of winter in the Northern Hemisphere and first day of summer in the Southern Hemisphere. Unofficial? Yes. Winter and summer start at the solstices by tradition, not official decree. Yet these solstices bring very real occurrences to our sky, which you can witness for yourself.

The day – from one solar noon to the next – is longest around now

This curved line is called an analemma.  It shows sun's declination - its annular distance from the celestial equator - and difference (in minutes) between time as measured by the clock and time as measured by the sun.  Click here to read more about this image.

This curved line is called an analemma. It shows sun’s declination – its annular distance from the celestial equator – and difference (in minutes) between time as measured by the clock and time as measured by the sun.

Happy solstice, everyone. The December solstice will come tomorrow at 23:03 Universal Time. At this instant, it’ll be at 5:03 p.m. for the Central U.S., or around sunrise for North and south America, sunset for far-eastern Asia, midnight for Africa and Europe, and noontime over the Pacific Ocean. We in the Northern Hemisphere will have our shortest day and longest night of the year. And yet – if you consider the word day in another light – the longest days of the year come each year in December for the entire globe.

Ursid meteors active around December solstice

Ursid meteors radiate from very far north on the sky's dome, near the Big and Little Dippers.

Ursid meteors radiate from very far north on the sky’s dome, near the Big and Little Dippers.

The annual Ursid meteor shower always peaks near the time of the December winter solstice, so, in 2014, look for some possible activity over the next several nights. This shower favors the more northerly latitudes in the Northern Hemisphere, but even at far northerly latitudes, it’s generally a low-key production, not nearly as exciting as the Quadrantids in early January.

Northern Cross stands upright in west on December evenings

The Northern Cross stands upright in the west on December evenings.

The Northern Cross isn’t as famous as its counterpart – the Southern Cross – visible from the Southern Hemisphere or the northern tropics. But the Northern Cross also looks like a cross, and it’s pretty easy to spot. It’s a large, noticeable star pattern.

The star Deneb marks the top of the Northern Cross, and the star Albireo marks the bottom. Tonight you can find the Northern Cross shining fairly high in the west at nightfall, as seen from mid-northern latitudes. It sinks downward during the evening hours, and stands proudly over the west-northwest horizon around mid-evening.

The Northern Cross is what’s known as an asterism. In other words, it’s not a constellation but simply a noticeable pattern of stars. It’s part of the constellation Cygnus the Swan.

Everything you need to know: December solstice 2014

Around the time of the winter solstice, watch for late dawns, early sunsets, and the low arc of the sun across the sky each day. Notice your noontime shadow, the longest of the year. Photo via Serge Arsenie on Flickr.

Late dawn. Early sunset. Short day. Long night. For us in the Northern Hemisphere, the December solstice marks the longest night and shortest day of the year. Meanwhile, on the day of the December solstice, the Southern Hemisphere has its longest day and shortest night. This special day is coming up on Sunday, December 21 at 23:03 UTC (5:03 p.m. CST). A fun fact about the coming solstice is that it occurs within about two-and-a-half hours of a new moon. No matter where you live on Earth’s globe, a solstice is your signal to celebrate. Follow the links inside to learn more about the 2014 December solstice.

Bellatrix, Orion’s third brightest star, means Female Warrior

11Dec01_430

The third-brightest star in Orion, Bellatrix, is often overlooked. And yet Bellatrix is such a wonderful star. The name means “Female Warrior,” which some find odd since the original Arabic title translates as “Conqueror.” But – throughout the world – women understand. Bellatrix represents Orion’s left shoulder. Although it appears only as the 22nd brightest star in our heavens, in reality it is a hot, blue giant some 240 light-years away.

December 2014 guide to the five visible planets

Skywatcher, moon, planet (looks like Venus) from Predrag Agatonovic.

Skywatcher, moon, planet from Predrag Agatonovic.

In December, 2014, Venus out briefly after sunset; Mars up the early evening; Jupiter shines from mid-to-late-evening to dawn; Saturn in the southeast predawn; Mercury lost in the sun’s glare.

See a star that changes its brightness

Artist’s concept of the star Sheliak, or Beta Lyrae. It’s really two stars that eclipse each other as seen from our earthly vantage point. Image via Fahad Sulehria at novacelestia.com.

Tonight, we zoom in on a variable star – a star whose brightness changes – near the bright star Vega in the small but distinctive constellation Lyra the Harp.

Everything you need to know: Quadrantid meteor shower

From mid-northern latitudes, the radiant point for the Quadrantid shower doesn’t climb over the horizon until after midnight.

The 2015 Quadrantid meteor shower is likely to produce the most meteors before dawn January 4, although in the glare of the almost-full moon.

Constellation Virgo represents a Maiden

2014-dec-16-moon-spica-night-sky-chart

Yes, we’re still talking about the predawn sky. Tomorrow we’ll shift into to evening sky. I can’t resist showing you these crescent moons in the east before dawn, during the part of each month when you’ll find them there. Tomorrow morning – December 17, 2014 – the bright star near the moon is Spica in the constellation Virgo.