The Crown Jewel of a Dark Night
Can you find Corona Borealis?
Thursday’s new moon is hidden amid the glare of the sun, but it reemerges Friday as a most slender, young crescent that you just might be able to see. You’ll need clear skies, an unobstructed view to the west-northwest and spot-on timing, as this moon appears low against the horizon for 15 minutes at most immediately following sunset. Brilliant Venus is just two degrees away, but you may need binoculars to pick out either from deep within the glare of twilight.
Night by night, the waxing crescent moon is easier to spot, appearing higher in the sky at sunset and remaining visible longer. Saturday at dusk it hangs below Jupiter in the west with Venus to its lower right. Sunday the moon is perched 10 degrees above Jupiter. By Tuesday evening, the moon shines close to the twin stars of Gemini, Castor and Pollux. To the other side of the moon is brighter Procyon.
While Jupiter and Venus appear briefly following sunset, Saturn is only then rising. The ringed planet rises in the southeast within an hour of sunset and is at its highest in the south around midnight. As daybreak nears, Saturn sets in the west-southwest.
This week’s moonless nights provide a dark background to explore the stars. Nestled between the bright stars Vega and Arcturus and to the east of the familiar shape of Hercules, look for a near-perfect semicircle of seven stars high in the east after sunset. This is the Northern Crown, or Corona Borealis. In the middle of the crown is its brightest star, Gemma, or Alphecca, the Pearl of the Crown, shining at second magnitude. In Arabic, Alphecca translates to the broken one. Gemma is a blue-white star 75 light years from Earth. It is more than twice the size of our sun and 60 times brighter.