Emerge From Your Hole And Wriggle At The Full Worm Moon

Tonight the moon is just shy of full and rises in the constellation Leo about half an hour before sunset in the east. This view shows it around 8 p.m. local time. Click to find when the moon rises for your town. Stellarium

Look around my neighborhood on a sunny March afternoon and you’d better be wearing sunglasses. Three to four feet of snow still covers the landscape and there’s more in the forecast for next week. What good fortune then that we have a full moon.

Like the namesake worms that emerge from the ground in warmer climes this month, the Full Worm Moon coaxes snowbound stargazers outdoors for a refreshing change in scenery. Since the time of full moon is in the middle of the day tomorrow (12:08 p.m. CDT), tonight’s moon will appear nearly as full as tomorrow night’s.

Every month the moon lines up on the opposite side of the Earth from the sun during full moon. We turn to face it in the east directly opposite the setting sun behind us in the west. Illustration: Bob King

You’ll notice a difference in rising times however. The moon just prior to full rises shortly before sunset, while a moon a bit past full rises after sunset. Tonight’s moon rises while with the sun still shining very low in the west; sky light will temper its contrast and color compared to tomorrow night’s moonrise in a darker sky.

The nearly full moon rising in the dark purple-gray band of Earth’s shadow two Aprils ago. A similar moon rises tonight. Notice that the landscape shows clearly along with a not-overly-bright moon. Credit: Bob King

That’s not all bad. When taking photos of the full moon and surrounding countryside or cityscape, it’s important that the brightness of the moon and landscape balance out, so neither is overly bright or dark. This will be easier tonight with the moon higher up in a darkening sky. Tomorrow night, by the time the moon is up, the landscape will be darker and the interval of time when they balance out briefer.

You’ve probably noticed how squished the moon looks when it first comes up. Stronger refraction from the thicker, denser air closer to the horizon “lifts” or refracts the bottom part of the moon upward, “squeezing” it into an egg-like shape. Once the moon’s higher up, air density is more uniform, refraction effects less and the moon looks round. Credit: Bob King

On the other hand, the best time to get pictures of a full moon all squished from refraction at the horizon will be tomorrow night. It will stand out better around the time of moonrise because the sky will be darker compared to tonight.

For more lunar perspectives, check out my 10 way to enjoy the full moon.


4 Responses

  1. Only 1 Lunar month before the big show on April 14 th.
    Already 2 families lined up with young ones that will join me.
    Can’t wait to see the look on the 2 5years old’s faces when they see the Moon entering the umbra for their very first time.

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