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Sky Watch by J. Alex Knoll

Help plot the stars and shine a light on light pollution

With the moon waning through pre-dawn skies, this week marks the year’s second Globe at Night backyard observing drive, which aims to enlist you in charting the night sky. The goal: “to raise public awareness of the impact of light pollution by inviting citizen-scientists to measure their night sky brightness and submit their observations to a website from a computer or smart phone.”

This nebula is alive with stars

As the sun sets, one of the first constellations to appear is Orion, already high in the southeast, and by 8pm looming in the south. With its geometric, hourglass shape, Orion is one of the easiest constellations to spot and one of the most rewarding to study. The brightest star is blue-white Rigel to the lower right, marking the hunter’s left knee. Opposite to the upper left is the red-giant Betelgeuse, punctuating Orion’s raised right arm.

Now Playing In the Sky Near You

Winter, spring, summer or fall, there’s always a blockbuster overhead on any clear night.     Mercury still clings to the west-southwest horizon a half-hour or so after sunset at week’s end. It is surprisingly bright, but you may need binoculars to pick it out amidst twilight’s glare. Catch this one while you can, as it’s on its final showing.

Libra’s Zubeneschamali is unique

If you’re up before the sun, you can’t miss Venus, which rises in the southeast by 6am. A half-hour later, this Morning Star is ablaze a good 30 degrees above the horizon, brighter than anything but the moon and the coming sun. As the horizon brightens, Venus climbs higher, growing dimmer until blinking out of view by 7:30am. Wednesday morning, January 29, look for Venus just four degrees above a thin, waning crescent moon before dawn.

The return of Venus and Mercury brings us a chance to see all five naked-eye planets

A day past full, Thursday’s moon rises as the sun sets. The bright light to its upper right is Procyon, of the constellation Canis Minor. Higher still is golden Jupiter, the brightest object in the evening sky aside from the sun and moon. A couple nights later on the 18th, the waning gibbous moon rises a few hours after sunset in the company of Regulus, the heart of Leo the lion.

A recent solar flare could present Northern Lights to Southerners

A powerful solar flare on January 7 launched a barrage of plasm our way, which has the chance of producing auroras at much lower latitudes than usual. Scientists expect the activity to begin before dawn Thursday, January 9, which is too late to help given this issue’s release that day. But solar astronomers don’t rule out more blasts to come, as this solar flare, technically called a coronal mass ejection, was caused by an eruption from a massive and very active sunspot, AR1944, which is facing earth head-on.

Our closest approach to the sun does make for the shortest season

Twilight Thursday and Friday evening reveals the new crescent moon low in the southwest with Venus blazing a few degrees away tight against the horizon. Venus sinks lower in the early evening sky over the next week, finally disappearing between the sun and earth on January 11. Then, after a few days absence, it reappears in pre-dawn skies, where it will blaze as the Morning Star until autumn.

This time of year a day is 30 seconds longer

Winter officially begins with the solstice Saturday, December 21. At 12:11pm EDT that day, the sun reaches its most southerly declination, standing still above the Tropic of Capricorn. For the roughly 90 percent of the world’s population that lives in the Northern Hemisphere, this is the first day of winter, the day of the longest night and the shortest day of the year.

Can the Geminids outshine December’s full moon?

The moon lights up the night this week, starting as a waxing gibbous, reaching full moon Tuesday and waxing slowly through the middle of the week. Look for the near-full moon beside the Pleiades star cluster Saturday.

While never the comet of the century, it piqued our curiosity

It’s official: comet ISON is no more. NASA confirmed Tuesday that after its first-ever venture from the outer limits of the solar system to the sun, the comet did not survive the onslaught of solar radiation. Born 4.5 billion years ago during the formation of the solar system, ISON had resided in the so-called Oort Cloud a full light-year away. Roughly a million years ago, perhaps after a cometary collision, ISON began its journey toward the sun.