Be on the lookout in the western sky during twilight tonight. The 2-day-old fingernail moon will join Venus in Gemini the Twins for an eye-catching sight. You’ll see them both starting about about half an hour after sundown, but the best views will be in late twilight when they’ll dazzle in a darker sky. That’s also the time to get the best views of the “dark” part of the moon, all the area to the left of the sunlit crescent lit by reflected sunlight from Earth’s clouds and oceans. Apollo astronauts described the earthlit moon as looking like snow-covered ground at night.
Who knows what other surprises you might see if you go out. No aurora was forecasted for last night but promptly at 10:15 p.m. a phalanx of faint rays appeared in the northwestern sky. When they disappeared five minutes later, I figured that was it. Wrong-o. Multiple rays kept the northern sky lively till well past midnight.
No space weather storms are forecast for tonight, but who knows? In an earlier blog, I mentioned that the Milky Way’s now putting in a fine appearance in the eastern sky, rising like so much smoke from a zillion galactic campfires. Although the moon has returned, it’s still too skinny to brighten the night, so we’ve got a few nights of dark skies left for spying the galaxy on the rise.
The three brightest stars in the photo are Deneb in the Northern Cross (left), Vega (top) and Altair in Aquila the Eagle. Connect them all to make a giant triangle called the Summer Triangle, one of the sky’s most familiar asterisms.