Having never lived where I could see a wide expanse of sky from my bedroom window, the path of the moon as always mystified me. It seems to appear unpredictably in one spot in the sky or another. I still get a childlike thrill when a come across one of those enormous moons when moon hangs low over a line of houses low on the horizon.
So I began this project to understand where is the moon in the sky at any given hour of night and day of the year. Where is the moon in the sky now? What is the path of the moon? This page is devoted to exploring this question. Unlike most blog posts, I’ll update it as I go along. I’ve taken this up because it isn’t simple, even with the wonder of the internet, to find understandable answers. As I discover that I can figure out, I am trying here to put it into ordinary english, instead.
Having never lived where I could see a wide expanse of sky from my bedroom window, the path of the moon as always mystified me. It seems to appear unpredictably in one spot in the sky or another. No one can forget when there’s one of those enormous moons when it hangs low over a line of houses on the horizon.
So I decided I should understand how the moon moves.
Okay. I’ve been getting a few things clear in my head:
The moon appears to move across the sky as the sun does, from east to west. I say “appears” because what is actually happening, of course, is that the earth is spinning around one half of a revolution, more or less. With the sun, it’s so dominant it’s almost impossible to think of it being the earth’s turning, not the sun’s moving that’s happening. We know it as a scientifically proven theory, but the psychological reality is still that the sun moves from east to west, not that the earth is spinning from west to east.
But the moon is different from the sun in the sense that it doesn’t dominate the sky in the same way. So it is somewhat easier to become conscious that the moon is just staying where it was and it’s we who are turning.
This is perhaps part of why it sometimes seems like the sun and the moon are moving in opposite directions, like some kind of cosmic seesaw. But this is false. The moon and the sun cross the earth’s sky in the same direction, because it is really the earth’s turning that accounts for the apparent movement of both.
Okay. That’s Part I. But there’s a whole lot more going on. Just to enumerate: the season (the tilt of the earth), the hour of the day or night, where we are in the moon’s monthly orbit around the earth, and where on the globe we are at the moment we’re looking at the moon.
Part II: The role of the seasons; the “tilt” of the earth.
The fact that the earth is spinning through space on a tilt is what gives us seasons. The earth holds this tilt as it goes around the sun. So the Northern hemisphere is heated by many more of the sun’s rays in July and August than it is in. It actually works as an image to think of a standard globe of the earth on a stand going around a light bulb while keeping the angle of the tilt of globe steady while going around the light bulb.
This same tilt, I read, affects where we’ll see the moon. I found this chart useful:
|Season||Position of Sunrise/Sunset|
But it must be realized that this is most precisely true of the beginning date of each season. On the first day of fall (tomorrow relative to when I am writing this) the moon takes a path from East to West.
This is only part of the answer however: It tells us where the moon will be at sunrise and sunset, but not where it will be in between these two times. Nor does it really explain to me exactly why this is so.
To be continued…