Crescent Evening Moon

July 05, 2019

The crescent moon is low in the evening this weekend, chasing the sun in the western sky. And as it moves away from the sun in the sky, it becomes more and more illuminated. This weekend it will go from a narrow sliver on Friday night, to a textbook sickle on Sunday night. Each night it will creep higher and higher in the western sky. And any telescope will give you a good view of the moon—even small toy telescopes may surprise you. And crescent moons are great to look at close up because the shadow accentuates craters, mountains, and the so-called “seas.” In fact, Friday night the shadow will reveal one of the best-named seas on the moon. The “Sea of Crises.” Below it, you’ll also be able to see the Sea of Fertility, and the adjacent Langrenus (lang-GREEN-us) crater. On Saturday night, you’ll see part of the Sea of Tranquility, where Apollo 11 landed just shy of 50 years ago. Sunday night reveals part of the Sea of Serenity, and a striking series of craters in the southern hemisphere.

And if you miss it this weekend, don’t worry. The moon will be an evening companion for another couple weeks. The full moon returns July 16th… 50 years to the day since the launch of Apollo 11.

And if you’re looking for more easy targets, look to the southeast for bright Jupiter. It’ll look like a particularly bright star that doesn’t twinkle. Less observant eyes may mistake Jupiter for an airplane. If you have a telescope, you’ll see more moons—Jupiter’s four largest “Galilean moons” Io, Ganymede, Callisto, and Europa.