Driftless Dark Skies: Walk When the Moon is Full

October 8th, 2016 by John Heasley

This fall is a marvelous time for a moonwalk.  The next three months, our calendar and lunar months align.  The new moon falls near the beginning of the month.  First quarter moon is a week later.  Full moon is mid-month.  Last quarter moon is the third week.  And then the cycle repeats.  It has been a real challenge for calendar creators to get the solar and lunar cycles to line up.  Our solar year is just under 365¼ days.  A lunation, time between new moons, is just over 29½ days.  So you get twelve moons in a year with 11 days left over.  Our Gregorian calendar is solar and ignores the lunar cycle.  Even though “month” comes from “moonth”, we have random months of 28-31 days.  The Islamic calendar is more lunar.  The month begins when the crescent moon is first sighted, and the year is 354 days long.  The Jewish calendar is a compromise.  The months are the length of a lunation, but an extra month is added about every other year to keep the lunar and solar cycles in sync.

moonrisefrankshillIt’s easy to spot the full moon rising.  Be outside when the sun is setting.  Turn your back to the sun, and watch the direction of your really long shadow.  That’s where the moon will rise.  It can be anywhere between northeast to southeast.  This fall, the moon rises between east and southeast.  Full moon happens when the Earth is between the moon and sun, so watch for moonrise about the same time as sunset.  It’s a time of balance.  While you’re facing east, you’ll see a pinkish glow called the “Belt of Venus” just above the horizon and the darker shadow of Earth below the pink.   There’s only one moment when the moon is 100% full, but the moon will appear almost as full the day before and after.  That gives us some slack for when it’s cloudy.

Stargazers often avoid the full moon because it dims so many stars.  Others fear the dark.  But the moonlight eases the transition from day to night, and there’s a wonder there worth seeing.  My favorite places for moonwalking in the Driftless Area are Wyalusing State Park, Wildcat Mountain State Park, and Kickapoo Valley Reserve.  KVR continues their popular program from last winter and offers four evenings this fall and winter to “Walk When the Moon is Full”.  We will gather at sunset/moonrise at the Visitor Center and hike down to Old 131 Trail.  KVR astronomy educators will have binoculars and telescopes set up for you to enjoy the highlands, maria, craters, and rays of the full moon.  We will also take a look at the planets and constellations while we enjoy the other sights, sounds, and smells of the moonlit world.  This will involve some moderate hiking in the dark on uneven and possibly slippery surfaces.  Participants have the option of remaining at the Visitor Center for stargazing.  Event is free, but please register so that we can send you weather updates.  Dates are October 15 (Hunter’s Moon), November 12 (Frosty Moon), February 10 (Snow Moon), and March 11 (Crust Moon)

I took my title from the children’s book by Wisconsin ornithologist and naturalist Frances Hamerstrom.  She tells the true story of taking her two children to walk every month when the moon is full.  Depending on the season, they meet up with deer, rabbits, possums, woodcocks, owls, fireflies, frogs, foxes, weasels and the other crepuscular creatures that live in the twilight time between day and night. 

John Heasley is an astronomy educator and stargazer who enjoys connecting people with the cosmos. He volunteers with NASA/JPL as a Solar System Ambassador. For more information about stargazing in southwest WI, like Driftless Stargazing LLC on Facebook and find out whenever there’s something awesome happening in the skies. Driftless Dark Skies appears monthly in the Voice of the River Valley. 

Thanks to Barbara Duerksen for sharing Frances Hamerstrom’s book with me.