Articles by J. Alex Knoll

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 2/23/12

Catch the Naked-Eye Five

How many planets can you spot?

The waxing crescent moon and Mercury appear low in the west-southwest after sunset Thursday. While the moon is easy to spot, Mercury is 10 degrees lower, buried amid twilight’s glow. Your chance to catch the innermost planet hinges between its own setting, around 6:45, and the sun’s glare, which doesn’t give way to full darkness until 7pm. Scanning the horizon with a pair of binoculars will help. And while the waxing moon moves on, Mercury gets easier to see the next few weeks...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 2/16/12

Shine a Light on Light Pollution

Citizen scientists add to the night sky’s picture

The waning crescent moon rises a few hours before dawn at week’s end, edging closer to the sun before reaching a new phase Tuesday. This week’s dark winter skies coincide with the Great Worldwide Star Count, going on this month through February 21. Sponsored by the GLOBE at Night Foundation, the goal is to enlist 15,000 “citizen scientists” to report their sightings from three constellations, Orion, Leo and Crux. Additional counts go on March 13-22 and April 11-20....

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 2/9/12

Spring’s Swimming Ducks

See if you can find Scorpio’s stinger stars Shaula and Lesath

Sunset reveals the two brightest planets, Jupiter, almost overhead, and Venus, high in the southwest. Equipped with a pair of binoculars or a small telescope, you may be able to spot a third planet, distant Uranus, which appears near Venus. The moon rises around 8pm Thursday, with ruddy Mars less than 10 degrees away. By 2am, now Wednesday morning, moon and Mars are high in the south, and with sunrise they are above the west horizon. Nearing its closest point to Earth in two...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 2/2/12

Spring’s Early Welcome

It’s all how you divide the year

The first week of February marks a seasonal milestone, as the sun hovers midway between its southernmost point above the Tropic of Capricorn on winter solstice and its position above the equator on vernal equinox. If you think of the year as a compass with the equinoxes and solstices the four cardinal points, then this cross-quarter day — one of four — represent the ordinal points, dissecting our seasons. Cultures around the world from the earliest days of...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 1/19/12

The Great Orion Nebula

Behind this glowing mass of cosmic gas is a stellar nursery

The waning crescent moon reaches new phase Monday, leaving our night skies free of its overpowering glow. As darkness settles and the stars come into view, the familiar outline of Orion is appears above the southeast horizon. Easily the most recognizable constellation, Orion has marched through the heavens and played a role in the mythology of every civilization and culture on earth. Each of the constellation’s stars is magnitude 2 or brighter, and...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 1/12/12

The Night’s Shifting Lights

Regardless of the time, there’s plenty to see

The waning moon rises before midnight Thursday and Friday, with ruddy Mars just a few degrees above. They are high in the south by 4am and in the southwest at dawn. Monday’s last-quarter moon rises after midnight, just a couple degrees below the bright star Spica. Golden Saturn trails a few degrees to the moon’s east, with the three forming a tight triangle. Before dawn Wednesday, look for the waning crescent moon at the head of Scorpio, while...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 1/5/12

Speeding Through Winter

Would you believe it’s our shortest season?

Thursday brings two celestial milestones: it marks the latest sunrise of the year and it marks perihelion, earth’s closest point to the sun. Intuitively, you might expect the closer to the sun we are the warmer the weather. However, the three million miles difference between perihelion and aphelion — our farthest point from the sun in July — is not near enough to account for the changing seasons. Instead, earth’s 231⁄2-degree tilted axis brings...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 12/22/11

Christmas Lights

Feast your eyes on the heavens above

Of the naked-eye planets, Mercury is the most overlooked. That isn’t for lack of brightness, as it outshines both Mars and Saturn. Nor is it a result of distance, given that it’s closer to us than is Mars. But so near the sun, Mercury never strays far from its blinding glare. Early Friday morning, however, the innermost planet reaches its farthest point from the sun, called elongation. This is also Mercury’s longest stretch of visibility: It rises in the...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 12/15/11

The Gathering Darkness

Five planets brighten these long nights

All the naked-eye planets decorate our night skies the next couple weeks, with the two brightest coming into view at sunset but all staggered throughout the dark hours. The sun sets around 4:45 this week. By that time you’re likely to see Jupiter presiding over the eastern skies. Look to the opposite horizon where Venus blazes even brighter in the wake of the setting sun. Venus sets within two hours of the sun. Jupiter, on the other hand, shines through much of the...

Article - Sky Watch by J. Alex Knoll; by J. Alex Knoll - 12/8/11

Basking in the Glow

Bright lights warm dark nights

We’re still a couple weeks from winter solstice, the day with the least sunlight for us in the Northern Hemisphere. But we’re already enjoying later sunsets one day to the next. Wednesday the 7th, old Sol sunk beneath Annapolis’s southwest horizon at 37 seconds past 4:43, the earliest sunset of the year. By the solstice December 21, the sun sets more than two and a-half minutes later at 4:47:03. December’s full moon Saturday is called the Yule Moon,...