Catch a very young crescent Moon this evening

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While the “SuperMoons” generally get the most buzz and hype I find hunting the very “young” and very “old” crescent Moon much more challenging, beautiful and rewarding.

This (Friday, 30 December) evening’s sliver thin 36 hour young crescent Moon will be the best opportunity for observers across North America in 2016 to observe a less than “two day old” Moon.

The “age” of the Moon is measured from the moment of “new” as it passes the Sun. We can only observe the moment of new during a solar eclipse. Some observers enjoy the challenge of seeing a very “young” Moon in the evening sky the first day or two after new or a very “old” waning crescent in the pre-dawn sky in the days prior to new.

The moment of “new” for lunation 1163 was 6:53 UT (2:53 AM EST) Thursday, December 29. According to Guy Ottewell in his “Astronomical Calendar” the record for naked eye observations of extremely young or old Moons is about 15 hours.

I find chasing very young and old Moons a delightful, but daunting, challenge and suggest you take up this challenge this evening about 30 to 50 minutes after sunset.

For those of us here in the North American midwest Luna will be about 39 hours “old” at 5:53 pm this evening. The graphics are screen shots generated using Stellarium and Starry Night CSAP7, showing the southwestern horizon at approximately 6pm EST.

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The Moon will be 18 degrees east of the Sun and about 30 degrees west of sparkling Venus and only 2.5% illuminated. Sweep the southwestern sky with binoculars or a telescope. The very thin lunar crescent will be hard to see in the twilight glow.

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I generated this graphic using Stellarium to demonstrate the razor thin crescent you can expect this evening. For those to the east the crescent will be slightly thinner and those to the west very slightly thicker.

Of course you’ll need a clear, low horizon to the west and a cloud free sky.

Start your search by measuring about three fists at arm’s length at about “5 o’clock” below and right of Venus. Ottewell suggests you send your results (positive or negative) to Brad Schaefer, Department of Physics and Astronomy, Louisiana State University if you make a serious attempt at this observation. Let me know how it goes here.

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