Monday’s solar eclipse can also pique our interest in moon-watching
Peterborough Examiner – April 5, 2024 – by Drew Monkman
As we cross our fingers that next Monday’s solar eclipse will be graced with clear skies, I’ve found myself thinking not only about the sun but also the moon. In order for a solar eclipse to occur, the moon has to be between the sun and the earth. This only happens in the new moon phase. But how many of us really know or pay attention to the moon’s phases?
For years, I was only vaguely familiar with the comings and goings of Earth’s nearest natural satellite. It was just “somewhere up there” and its phases were something of a mystery. I came to realize, however, that paying closer attention to the moon enhances an appreciation of nature and the changing days, weeks, months and seasons. With early now spring upon us and longer, more comfortable evenings, this is an ideal time for moon-watching.
Eclipse viewing: Head south
Before delving into the moon’s phases, it’s important to say a few words about the eclipse itself. This is a monumental event and one you don’t want to miss. The most important thing to keep in mind is that only those locations in the centre of the moon’s shadow will experience a total eclipse (totality). And only when the sun is 100% blocked by the moon – not 99% like in Peterborough – is the full spectacle revealed. The other-worldly highlights include the sun’s dazzling white corona shining all around the moon’s black disk, “streamers” from the corona extending across the darkness, shadow bands racing across the landscape, weird colors in the sky, a noticeable drop in temperature and even visible stars and planets. It’s often described as the most spectacular event one can see in the natural world
Communities such as Port Hope and Cobourg on the Lake Ontario shoreline are the places to be take in the show. In Cobourg, the partial eclipse begins at 2:06:57 p.m.; totality lasts from 3:20:53 to 3:22:18 (1m 25s); and the rest of the partial eclipse ends at 4:32:53 p.m. In Port Hope totality starts at about the same time but lasts only 55 seconds. If you can’t get away, maximum eclipse in Peterborough occurs at 3:21 p.m.
If there is a thick cloud cover, the sky will only darken a little during totality. However, if the clouds are high and wispy, totality should still be visible. Remember to wear special eclipse glasses with filters.
Moon 101
It’s thanks to the moon that an eclipse occurs at all. Like the sun, the moon appears to rise in the east and set in the west. It follows roughly the same path as the sun through the sky and is visible during the day as much as at night. But, unlike the sun, the moon rises each day an average of 50 minutes later than the day before. We see the moon because it reflects the light of the sun.
It takes the moon 29 1/2 days to go through the full cycle of the eight distinct phases described below. Why not challenge yourself to see all eight over the coming weeks? I’ve included the dates to see each phase. Because some of the phases last more than one day, you’ll have several opportunities to get out and observe them. To see a moon phases calendar for the entire year, go to https://rb.gy/uf46mj
The moon’s phases
1. New moon (April 8): The new moon rises and sets with the sun and stays close to it during the day. Because the moon is between the earth and the sun in this phase, the sun shines only on its far side making the moon invisible. A solar eclipse is the only time to actually see the new moon.
2. Waxing crescent (April 9-14): The moon now rises and sets shortly after the sun. It is especially striking in the evening twilight, low in the west. Earthshine (sunlight reflected off the earth, onto the moon and back again to our eyes)dimlyilluminates the moon’s surface to the left of the crescent. Looking like the rounded part of a D, the waxing crescent moon is “Developing” towards the full moon. This phase is poetically described as the moon’s “ashen glow” or the “old moon in the new moon’s arms.” Earthshine is more pronounced in April and May than at any other time of year.
3. First quarter (April 15): Like the last quarter phase, this is the familiar “half-moon.” It’s called a quarter moon, however, because it has completed one quarter of its cycle. A first quarter moon rises around noon and sets around midnight. This is the best moon phase for looking at the moon’s surface through binoculars or a telescope.
4. Waxing gibbous (April 16-22): The word gibbous means “like a hump.” The somewhat football-shaped waxing gibbous moon rises late in the day and shines most of the night. Within a few days it looks very similar to the full moon.
5. Full moon (April 23): The beautiful full moon rises at sunset and sets at sunrise. It often appears like a huge orange ball as it climbs above the eastern horizon in the evening. In this phase, the moon is on the side of the earth farthest from the sun, so sunshine lights up its entire visible side. The full moon also appears to be larger at moonrise than when it is riding high in the sky. This is simply an illusion rooted in the way our brains process visual information. Some Anishinaabeg indigenous peoples call the April full moon “Popogami Giizis” (Poh-poh-gah-mi Gee-zhes) or Broken Snowshoe Moon.
6. Waning gibbous (April 24-30): The waning gibbous moon rises after sunset and once again becomes football-like in appearance. Now, however, it resembles the rounded part of a C. The moon is “Crumbling” away. You often see this phase in the west in the early morning. It can be quite striking as it almost seems to float against the pale morning sky.
7. Third (last) quarter (May 1): This “half-moon” phase rises in the middle of the night and sets at mid-day.
8. Waning crescent (May 3-6): What is left of the crumbling moon rises and sets just before the sun and stays in the sky most of the day. It is exquisitely beautiful at dawn.
Activities to try
For a better understanding of the moon’s phases, try the following activity. All you need is a strong flashlight, a tennis ball or an orange, and a pencil. In a dark room, place the flashlight (or similar light source) on a shelf or step-ladder at about eye level. Stick the pencil into the ball. Stand facing the light, holding the ball out in front of you at arm’s length and a little higher than your head. You’re looking at the new moon, since only the back of the ball is illuminated. Rotate slowly to the left, keeping the ball in front of you. Soon you’ll see a little crescent form (waxing crescent phase). Keeping turning until you see the entire right side of the ball illuminated. This is the first quarter. Rotating a little further, you’ll see the football-like waxing gibbous phase. When your back is to the light, the full moon appears. As you continue, you’ll be looking at the waning gibbous, the last quarter and the waning crescent. A full rotation brings you back to the “invisible” new moon.
Finally, here’s a mnemonic I came up with years ago to help my students know at a glance whether the moon is waxing or waning – in other words, whether the illuminated portion is growing larger or smaller. It goes like this: “Light on right, moon soon bright. Night on right, moon soon out of sight.”
“Light” refers to the illuminated part of the moon; “bright” refers to the full moon; “night” refers to the dark part of the moon, and “out of sight” is a reference to the new moon never being visible. If you forget whether “light” or “night” comes first in the mnemonic, remember that L comes before N in the dictionary.
