By the Light of the Moon
As the sun sets near 8:30 Friday, look for an ever-so-slender crescent moon hugging the west-northwest horizon. Just two days past new phase, only about five percent of the lunar disk will be illuminated. To spot this sliver of moon, you’ll need an unobstructed view of the horizon, and binoculars may help you to pick it out from the lingering glare of dusk.
The next night, the waxing crescent moon is higher above the horizon at sunset, and now more than 10 percent of its face is aglow. Ten degrees above the moon’s upper tip is golden Pollux with its twin, Castor, a few degrees higher still. Equidistant below the moon is the bright star Procyon of the little dog Canis Minor.
By Sunday, the moon is almost 30 degrees above the horizon with darkness and is surrounded by the stars of the Zodiac’s faintest constellation, Cancer. Four stars, none shining brighter than third magnitude, make up its Y shape. More noteworthy than the constellation itself is the fuzzball of light at its center, the Beehive Cluster, known historically as Praesepe. However, armed with a small telescope or even binoculars, you will see, as did Galileo in 1609, that “the nebula called Praesepe is not one star only, but a mass of more than 40 small stars.” Today’s astronomers, armed with far greater optics, have identified more than 200 stars belonging to this cluster.
By Tuesday the moon is just one day shy of first-quarter and shines about seven degrees south of Regulus, the heart of Leo the lion.
If you’re up in the hour before sunrise, this week around 5:40, look to the east for Venus, Mars and Mercury. While you should be able to spot Venus with the unaided eye, you will need binoculars if you hope to track down the other two. Don’t confuse brighter Venus for Jupiter, much higher in the east.