Will You See Tonight’s Silvery Sliver Of A Moon? / Aurora Watch Jan. 1-2

An 18-hour-old crescent moon photographed with a 12-inch telescope on April 22, 2012. An even younger moon may be visible tonight in the southwestern sky shortly after sundown. Credit: John Chumack and Maurice Massey

2014 begins with a chance to spy an exceptionally thin crescent moon shortly after sunset and possibly the shimmer of aurora at nightfall.

The thin crescent about 1.5 days before new moon on Jan. 21, 2012. Credit: Bob King

The moon’s age is determined by how many hours or days have passed since new moon phase. New moon occurs once a month when the moon lies in nearly the same direction as the sun in the sky. No one can see a new moon because it stays very close to the sun and hides in the glare of daylight.

Under favorable circumstances it’s not too difficult to spot a 1-day-old moon, referred to as a young moon because it’s the first or youngest bit of moon we see after new moon. Young moons are delicate, faint and tucked far down in the twilight glow shortly after sunset.

Spotting a moon fewer than 24 hours old requires planning. You need a flat horizon, haze-free skies and a pair of binoculars. Being on time’s important, too. Be sure to arrive at your observing spot shortly before sundown. Knowing the point on the horizon where the sun sets will guide you to the crescent’s location.

Venus – still visible low in the southwestern sky at dusk – will also be a big help tonight. It’s perfect for getting a sharp focus with your binoculars, essential for seeing the faint lunar crescent clearly. The planet hovers some 7-8 degrees to the moon’s upper left. When you focus on it, you’ll be in for a surprise. I wish I could tell you, but that would spoil the fun.

Diagram showing the sky facing southwest from the Minneapolis area 20 minutes after sunset or at 5:02 p.m. today. The moon will be about 3.5 degrees high at the time. The view will be similar across the Midwest. Further west, the moon will be somewhat higher and closer to Venus. Stellarium

New moon occurred at 5:14 a.m. (CST) today, making tonight’s crescent approximately 12 hours old for skywatchers in the Midwest. Since the moon’s orbit carries it moves east of the sun its own diameter every hour, skywatchers in the western U.S. will have a somewhat easier time of seeing it. From Denver, the moon will be 13 hours old, San Francisco 14 hours and Hawaii 16 hours.

Given that the record for the earliest naked eye sighting of the moon after (or before) new phase is 15 hours 32 minutes and the earliest binocular/telescope observation is 11 hours 40 minutes, most of us will need some kind of optical aid to spy tonight’s silvery sliver.

I recommend a pair of binoculars in the 35mm-50mm range with a generous field of view. Oh, and don’t forget your heavy coat and boots for warmth. Locales with open horizons are generally the windiest places in the world.

Now here’s a lovely view. The waning crescent moon rises above Earth’s atmosphere as seen from the International Space Station. Credit: NASA

Here’s a checklist of what you’ll need:

* Figure out your sunset and moonset times HERE. That way you’ll know exactly when and for how long to watch.

* Thank your lucky stars if the sky is extremely clear and without haze or clouds in the southwest direction.

* Arrive no later than sunset, face toward the direction of sunset and focus your binoculars or telescope on Venus, that brilliant “star” you’ll see about 1 to 2 fists high in the southwestern sky.

* Start looking for the moon 10 minutes after sunset by slowly sweeping the sky just a few degrees above the sunset point. Continue to look for the next 25 minutes giving your eyes an occasional rest and checking focus. You’ll be looking for the thinnest of the thin, no more than a partial arc scratched across the deepening blue.

* If you spy the moon in binoculars, carefully lower them and try to find the moon with your naked eye.

Whether you have success of not, I welcome anyone who attempts this observing challenge to share your observation in our comments section. Good luck to you!

The coronal hole – photographed on Dec. 30 in far ultraviolet light – that might could lead to a chance at seeing the northern lights tonight and tomorrow nights. Credit: NASA

Later this evening and tomorrow as well, there’s a chance that a high-speed stream of particles cut loose from a coronal hole – a open magnetic portal in the sun’s corona that allows electrons and protons to flow freely into space – could kick-start minor auroras at high latitudes. Sometimes that means folks living in southern Canada and along the U.S. northern border can see them too.

You’ll find no lack of sunspot groups on the sun today. This photo was taken by NASA’s Solar Dynamics Observatory this afternoon at 12:15 p.m. CST. Moderate solar flares are possible from Region 1944 (just entering the disk) and departing 1936. Credit: NASA

The sun has recently been more active with an M-class flare yesterday from the 1936 group and the potential for more. Be on the lookout this evening and next for a small display. With little to no moon in the sky, these are good times to look for auroras.

11 Responses

      1. Sean

        Bob, correct as usual – as of 8:42 AM ET, it was naked-eye – BIG TIME – with filtration of course. under 10x magnification a very complex-looking system, with the big dark core, a somewhat smaller one, and then a string of even smaller dark ones arrayed widely along a curved line.

  1. Sean

    1944 does look interesting! i made an observation of the sun prior to 11AM EST using 10X50’s, held very steady by leaning them on the window sill, and was able to see about 8 dark spots on the equatorial region, but they were all from #’s ’38 to ’36. And i was pretty careful as i searched around, including checking near the sun’s N and S poles to make sure i wasn’t missing anything. I doubt i missed anything as big as that, so i am gonna assume that any significant portion of the sunspot rounded the bend just after that. it should be great, especially around here in a couple of days when “Hercules” clears out of New England. As for that YOUNG moon, no way, as we had some high clouds in the evening particularly toward the horizon. on the E coast we were at a disadvantage for this one. on the Calsky “young crescent” page it doesn’t even list it as a possibility for my location, and depending on settings it WILL mention marginal situations, along with relevant Yallop criteria info, including sightings which would require a telescope. another observation i didn’t attempt was that of a daytime Venus as sunset approached, which i am hoping to make with binoculars in hopes of monitoring the changes in the crescental appearance, since the amount of haze/moisture in the air discouraged me so i napped thru any potential breaks around sunset time. oh well, better luck by Saturday as far as the weather i hope.

    1. astrobob

      Hi Sean,
      We were so close to possibly seeing the young crescent but also had “inopportune” clouds. I did see Venus as a crescent though in my 300mm telephoto lens. You’ll catch it soon hopefully – there’s still time.

      1. Sean

        yep caught it today. looking good! but SO much closer to the sun than when i last saw it, last weekend. started looking 4:11PM (time i spotted it last time), of course looking closer to the sun’s position than where i saw it then, (i wanted to do it naked-eye, which i did,) but couldn’t find it and returned a couple more times before finally glimpsing it at 4:27, just about sunset. it was kind of a tough naked-eye spotting at that time even, so no wonder i didn’t see it earlier. good chance of clear enough skies tomorrow to view it again, now that i know quite precisely where to look. then cloudiness forecast for Sunday and i have to work during the visibility period Monday thru Wednesday so that might be it for me till the other side.

  2. Stargazer

    I saw the sliver of moon this evening (1/2/14) as I was driving in the car. Absolutely beautiful and striking for how thin it was. I had no trouble seeing it with the naked eye in central Wisconsin (but we live in a rural area with little light pollution). It’s nice to find out why the moon looked so strange. Thanks!

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