The Moon is nearly back to the point in its orbit where its dayside directly faces the Sun, and all that we see from our perspective is a thin curve. When we think of the way the Moon seems to change over the course of a month, we think of phases.
But frequent Moon observers know that the Moon also appears to twist, nod, and roll slightly during its journey across the sky, allowing us to peek around the Moon's shoulder and catch glimpses of the farside. This phenomenon is called libration. Because the Moon's orbit is not perfectly circular, its distance from Earth and its speed in orbit both change slightly throughout the month. When the Moon is farthest from Earth and orbiting at its slowest, its rotation gets a little ahead, and we see a bit more of its western side.
Finally, the Moon appears to tilt back and forth like a metronome. Earth has a tilt of If you look left, the ramp slopes up. If you look right, the ramp slopes down. In front of you, the horizon looks higher on the right and lower on the left. If you turn around, the horizon appears to tilt the opposite way. Every two weeks, we have to look in the opposite direction to see the Moon, and the ground beneath our feet is then tilted the opposite way as well. The best times to see a daytime Moon are perhaps during the first and last quarter phases, when the Moon is high enough above the horizon and at about 90 degrees from the Sun in the sky.
The crescent through quarter phases are high in the sky during the day, but the daytime gibbous phases can be glimpsed only just before the Sun sets. Since the Moon is tidally locked, we always see the same side from Earth, but there's no permanent "dark side of the Moon. The new Moon occurs when the Moon, Earth, and Sun all lie along approximately the same line.
Since the Sun is behind the Moon from Earth's perspective, the side of the Moon that faces Earth is dark. At full Moon , the three bodies also lie approximately in a line, but this time, the Moon is on the opposite side of Earth, so the Sun illuminates the whole side facing us. At first quarter and last quarter , the Moon lies perpendicular to a line between Earth and the Sun.
We see exactly half of the Moon illuminated by the Sun — the other half lies in shadow. The "quarter" used to name these phases refers to the respective fraction of an orbit that the Moon has completed since new Moon. The illuminated part of the Moon gradually transitions between these phases. To remember the in-between phases you'll need to understand these terms: crescent, gibbous, waxing, and waning. Crescent refers to phases where the Moon is less than half-illuminated, while gibbous means more than half is illuminated.
After new Moon, a slice of reflected sunlight becomes visible as a waxing crescent. The lunar crescent grows until first-quarter Moon. As the sunlit portion of the Moon continues to increase to more than half of the Moon's face, the Moon turns waxing gibbous. Then, after the full Moon the sunlit fraction begins to decrease again though it still takes up more than half the face of the Moon to make a waning gibbous and then a third-quarter Moon. The slice of sunlight continues to decrease until the moon is a waning crescent and then a new Moon.
The whole cycle from new Moon to new Moon takes about The Moon's phases are actually related to orbital motion, and there's a simple and fun observation that shows how they're connected. All you'll need is a Ping-Pong ball to simulate the Moon—actually, any small, white sphere would work.
Then head outside about an hour before sunset, or around the time of a first-quarter Moon. Find the Moon in the southern part of the sky, then hold the ball up at arm's length right beside it. The four primary phases of the moon occur about a week apart, with the full moon its most dazzling stage. During the full moon on Nov. The eclipse will peak at a. Times and dates are in UTC time. If you need equipment for viewing the moon, check out our guide to the best telescopes and the best telescopes for kids.
How to photograph the moon using a camera: techniques, kit, and settings. How to observe the moon with a telescope. What you can see in this month's night sky. Best cameras for astrophotography. The moon, like Earth, is a sphere, and it is always half-illuminated by the sun. As the moon travels around Earth, we see more or less of the illuminated half. Moon phases describe how much of the moon's disk is illuminated from our perspective.
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