Go young moon hunting this week

The photo above was taken in November 2017 by Patrick Casaert in Meaux, France. Notice that this very young moon appears sideways with respect to the bottom of the photo. If you’re in the Northern Hemisphere – and you see the moon on November 8, 9 or 10, 2018 – it’ll likely be oriented sideways to your sunset horizon. That’s because – in autumn – the young crescent moon is located to the side of the sun in our evening sky, not above the sun as it is right now for the Southern Hemisphere (where it’s spring).

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On November 8, 2018, you might (or might not) spot the young moon in your western sky after sunset. Generally, it’s difficult to catch a pale, whisker-thin waxing crescent moon that’s less than 24 hours old (24 hours past new moon). New moon was November 7 at 16:02 UTC.

Exactly 24 hours after this month’s new moon – that is, at 16:02 UTC on November 8, 2018 – the line of sunset crosses western Europe and Africa. By the time sunset reaches the Americas, the moon will be well over 24 hours old. Image via U.S. Naval Observatory.

So Asia will have a tough time spotting the moon on November 8, but your chance to see it will improve as sunset comes to increasingly western longitudes. As the sun sets for western Europe and Africa on November 8, the moon will be approximately one day old. In that part of the world, the moon will most likely set somewhat less than one hour after sunset.

In the Americas on November 8, the moon will be more than a day old and therefore easier to spot. Still, the autumn angle of the ecliptic will keep the moon low in the twilight sky. You’ll have to search to see it!

If you miss the young moon at dusk November 8, try again on November 9 or 10. Day after day, a wider crescent moon will stay out later after sunset and will be easier to catch at early evening, as shown on the chart below:

At northerly latitudes, like those in the U.S. and Europe, it’ll be a challenge to spot the young moon, plus the planet Mercury, in the glow of evening dusk on November 8, 2018. Easier on November 9 and 10!

Live in the Southern Hemisphere? Given an unobstructed horizon in the direction of sunset, you have a good chance of catching the young moon near the planets Mercury and Jupiter on or near November 9, 2018. Will you see it on November 8 (not shown on chart)? Maybe!

As for the Americas, the moon will be well over 24 hours old at sunset, and, for the most of the Americas, the slender crescent will stay out for over one hour after sundown. All the same, you’ll want to find an unobstructed horizon in the direction of sunset for your young moon quest. Binoculars may come in handy as well.

View larger. | Peter Lowenstein caught a very young moon (about mid-photo, just above the cloud bank) and Jupiter (to the upper left of the moon) with the camera, but not the eye alone, about half an hour after sunset on November 8, 2018, from Mutare, Zimbabwe. Congratulations Peter!

Want to know the age of the moon at sunset for your part of the world? Click here and remember to check the Moon phases plus Moonrise and moonset boxes. (For example, at Philadelphia, Pennsylvania, the moon is 29 hours 49 minutes old at sunset November 8, because the new moon occurred at 11:03 a.m. local time on November 7 and the sun sets at 4:52 p.m. local time on November 8.)

Do you know your cardinal directions and are you familiar with the concept of azimuth? If so, you can obtain the azimuth reading of moonset (or sunset) by way of the U.S. Naval Observatory (remember to check the moon or sun as your celestial object of interest), or via TimeandDate.

Or, more simply, you can search for the young waxing crescent moon, with the unaided eye or binoculars, near the sunset point on the horizon. For a double bonus, seek out the planet Mercury, too, although this world will be considerably easier to spot from the Southern Hemisphere.

Read more: Mercury visible at southerly latitudes

Bottom line: These next several days – November 8, 9 and 10, 2018 – look for the young waxing crescent moon in the western sky after sunset. With each passing day, the lunar crescent will widen, to appear higher up in the sky at sunset and to stay out later after dark. Good luck!

Bruce McClure