The Northern Hemisphere’s full Harvest Moon has passed. Now the moon is in a waning gibbous phase, which means it rises in the east later and later each evening. Look east before going to bed tonight to catch the moon over the eastern horizon. Then look in the west after sunrise tomorrow – on the day of the equinox – or in the next few mornings to see the daytime moon over your western horizon.
When is the best time to see the moon in the sky during daylight hours?
The daytime moon is up there much of the time, but, because it’s pale against the blue sky, it’s not as noticeable as the moon at night.
The most noticeable moon at night is the one farthest from the sun in the sky. That would be around the time of full moon each month, when the moon is 180 degrees from the sun, on the opposite side of the sky’s dome. Full moon was on September 19, at 11:13 Universal Time.
A full moon rises around sunset and sets around sunrise. But now the moon is in a waning gibbous phase – rising later each night – and setting in the west later each day after sunrise.
So, in the next several mornings – after sunrise – look for the waning gibbous moon in the west during the morning hours. At mid-northern latitudes in North America, the moon will set at roughly 10 a.m. on September 22, and about one hour later each day thereafter. Elsewhere around the world, the moon will set at a similar time at mid-northern latitudes. South of the equator, the moon will set sooner after sunrise.
By the way, the moon is up during the day half the time. It has to be, since it orbits around the whole Earth once a month. Sometimes the daytime moon is hard to see because it’s so near the sun in the sky. And consider that if the sun is low in the sky, a crescent daytime moon might be high in the sky, so that you’d have to crane your neck, looking up, to notice it.
Ordinarily, we don’t look up during the day to see such a thin crescent moon. That’s one reason people are sometimes surprised to learn the moon is out so often during the day.
Day by day, the lighted portion of the waning gibbous moon will shrink and the half-lit last quarter moon will come on Friday, September 27. Watch for the daytime moon to climb higher and higher into the western sky after sunrise all this coming week!
Bottom line: Starting around the September equinox 2013, look for the daytime moon in the west after sunrise!