How to Spot a Young (or Old) Moon Within 24 Hours of New

 

Can you find the Moon at right? Even this is over 24 hours old!

What is the thinnest crescent Moon you can see? Can you see the Moon within 24 hours of New phase? The answer to the first question will vary but the answer to the second is undeniably a 'yes' as it is very possible to see the Moon within 24 hours of New. For even better news, spring is an ideal time to look.

Young/Old Moons (within 24 hours of New) are, besides quite aesthetic, rare, very rare. To sight a Moon within 24 hours of New requires all the conditions to line up just right. If everything goes perfectly, on the day after/before New Moon (or even on the same day depending on the time of New), just past sunset/before sunrise, a wire-thin crescent will pop out low on the horizon. Needless to say, when dealing with a Moon less than 2% illuminated, binoculars are a must.

So here is why the Young/Old Moon is so difficult to spot:

1. Timing. If New Moon is timed too close to sunset/sunrise, it will be lost in the Sun's glare on the day of New Moon and will be way past the 24 hour window at its first/last visibility for the cycle. While pretty, a 36 hour Moon is no challenge, pure and simple. Look up and find it.

2. Clouds. If it's cloudy, there's no seeing the Moon. In my Northeast Ohio area, spring and fall are 50/50 odds for a clear sky, at best.

3. Light. Young/Old Moon hunters are forced to fight the Sun With the Moon under 2% lit, just the act of spotting the Moon low on the horizon in such light conditions is a challenge because that is where the Sun is. A saving grace can be a nearby planet or bright star. If you can use a bright star or planet as a marker, it is a lot easier to estimate where the Moon will appear once the sky gets dark enough.

4. Haze. Even more so than during the day, haze makes its presence known at dusk, looking similar to wispy clouds on the horizon. While the biggest problem during the summer, haze can even appear in winter, too. Even a crystal-clear day can produce haze on the horizon at dusk. While the haze will quickly dissipate come dark, that's too late for the Young Moon. As a way to estimate haze before dark, look at the daytime sky. The deeper the blue, the lower chance of haze ruining the show. The good news, come fall and Old Moon season, the haze will be long gone as dawn approaches.

5. Horizon Obstructions. Buildings and trees can play havoc with the horizon as Young/Old Moons will be within 10 degrees of it. What does that look like? Hold a fist vertical at arm’s length to simulate 10 degrees, then go outside and see how your surroundings do. Chances are, you’ll have to scout a good observation sight in advance if you live in a built-up area.

Now for the good news: spring is Young Moon season. Because of the near vertical ecliptic at sunset, the waxing Moon will hang higher in the sky now than any other time of year, which is good. For Young Moon Hunters, March through May (add February and/or June depending on time of month New Moon falls) is an ideal time to look.

On the other end of the scale, Fall is Old Moon season as the ecliptic is nearly vertical from September through November at sunrise (add August and/or December depending on New Moon’s time of month), making this the ideal time to spot an Old Moon, one within 24 hours of becoming New again.

As for this spring's Young Moon season, thin crescents will appear on March 14, April 12, May 12, and June 11. Of the four, only one will be a true Young Moon (April 12) and only for those people living in the Eastern and Central Daylight Time Zones. Mountain Time and West? The Moon will be over 24 hours old, but still worth a look as few people have ever seen a crescent that thin.

Whichever time (hopefully both!) you plan to hunt a thin Moon, give it a try it if it's clear.

In need of inspiration, here you go for some of my pictures!

A 17 Hour Young Moon (holy cow!)
A 19 Hour Moon (featured on Spaceweather’s home page)
A 23 Hour Moon

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