Seek for a young moon after sunset

For a number of intrepid sky watchers, the hunt for the young moon counts as great sport. Seeking out a young moon that might – or might not – fleetingly show itself as a pale, skinny crescent in the western evening twilight demands fortitude and patience. What’s more, binoculars may come in handy for this young moon quest.The chances of catching the young moon after sunset on September 29, 2019, vary around the globe. It’s quite difficult to catch a young moon that’s less than one day (24 hours) old, and for the world’s Eastern Hemisphere, the moon will be less than one day old as the sun sets on September 29, 2019.

Line of sunset aligns with the prime meridian one day after new moon.

Quite by coincidence, the line of sunset pretty much aligns with Earth’s prime meridian one day after new moon (2019 September 29 at 18:26 UTC). By the time that the line of sunset reaches Central Time Zone in North America, the moon will be about 30 hours old. Map via EarthView.

The further west you live on the Earth’s globe, the better are your chances of spotting the young moon after sunset September 29, 2019. That’s because the moon is somewhat older when the sun sets at more westerly longitudes.

Click here to find out the moon’s setting time in your sky, remembering to check the moonrise and moonset box.

Also, the further south you live, the better are your chances of catching the young moon. That’s because the ecliptic – the approximate monthly path of the moon in front of the constellations of the zodiac – hits the sunset horizon at a steep angle in the Southern Hemisphere yet a a shallow angle in the Northern Hemisphere.

However, this particular young moon swings a maximum 5 degrees (10 moon-diameters) north of the ecliptic (5 degrees in ecliptic latitude). That erases much of the Northern Hemisphere’s disadvantage. This time around, the Northern Hemisphere finds itself in a better position than it usually does for spotting an early autumn young moon.

Click here to find out the present ecliptic latitude of the moon.

Seeing the young moon near the planets Venus and Mercury in the Southern Hemisphere

It’ll be easier to view the planets Mercury and Venus, plus the star Spica, from the Southern Hemisphere, because of the steep tilt of the ecliptic. Contrast with the feature sky chart at top for mid-northern latitudes,

Click here to know the moon’s place upon the zodiac.

The young moon isn’t the only world that’s tantalizing us at evening dusk, and may require binoculars to be seen. Two planets – Mercury and Venus – sit low in the west after sunset, and then follow the sun beneath the horizon before nightfall. You’re more likely to see Mercury and Venus from the northern tropics and the Southern Hemisphere, where the tilt of the ecliptic – pathway of the moon and planets – is much steeper than at northerly latitudes.

Wherever you may live, it is to your advantage to find an unobstructed horizon in the direction of sunset for your young moon search. The young moon will be hard to catch on September 29. If you miss it, then try again on September 30, when a somewhat wider crescent will be higher up after sunset and will stay out longer after sundown.

Bruce McClure