While winds and snow in my neck of the woods guarantee an overcast night, you might be more fortunate. If so, I encourage you to look for a very young and thin lunar crescent at dusk tonight. For U.S. skywatchers the moon will be anywhere from 21.5 hours old (East Coast) to 24.5 hours old (West Coast) and visible between 20-45 minutes after sundown 4-5 degrees high in the southwest.
You can use the planet Venus, now moderately low in the southwestern sky, and the sunset point, where the lingering glow along the western horizon is brightest, to help you pinpoint the moon.
Not many people get to see a crescent that’s only a day (or less) old and few things in the heavens are as beautiful. The moon looks frail and fragile enough to simply dissolve into the sky – a sight you won’t soon forget. You’ll need an open horizon to the southwest, clear skies and pair of binoculars to fall back on.
As you study the moon in binoculars, you’ll notice right away the skinny arc isn’t smooth but ragged or broken along its length. These seeming breaks are caused by oblique lighting on crater walls and mountain peaks creating shadows long enough to bite into and hide portions of the moon’s edge.
While spotting a day-old moon takes a little effort, anything under 20 hours requires careful planning as the moon is that much thinner, closer to the horizon and sets even earlier. The record for youngest moon spotted with the naked eye goes writer and amateur astronomer Steven James O’Meara, who nabbed a 15 hour 32 minute crescent in May 1990.
West Coast skywatchers have the opportunity to challenge that record on Jan. 1, 2014. New moon occurs at 3:15 a.m. Pacific Time that day; by sunset (5 p.m.) the crescent will be just 14 hours old fifteen minutes after sunset. Tough one! That’s why it’s OK to cheat using binoculars. The record for youngest moon ever seen with optical aid goes to Mohsen G. Mirsaeed of Tehran on September 7, 2002 at just 11 hours 40 minutes past new.
The ultimate record, which will never be broken, is 0 hours past new. It was set July 8 this year when French astrophotographer Thierry Legault photographed the new moon in the middle of the day. No, he never saw it with his eye; only the camera recorded the unique moment.