2. Waxing Crescent: set the movable piece so that the waxing crescent Moon is setting. Given the location
of the Sun at 9 p.m. on the dial, we see that the waxing crescent Moon sets at 9 p.m. Moving the
waxing crescent to its rising location in the east will show that it rises at 9 a.m. Rotate the top piece so
that the Moon is traveling across the sky above the horizon; notice that the right side of the waxing
Moon as seen by the observer is illuminated by the Sun.
The user should notice that during a given night, as the Moon and Sun cross the sky from east to west,the phase remains the same throughout the night. In other words, the angle between the Sun and Moon
45° for crescent, 90° for quarter, and 135° for gibbous, is constant throughout the night as the Earth rotates
underneath the distant Sun, Moon, and stars.
2. Waxing Crescent: set the movable piece so that the waxing crescent Moon is setting. Given the locationof the Sun at 9 p.m. on the dial, we see that the waxing crescent Moon sets at 9 p.m. Moving thewaxing crescent to its rising location in the east will show that it rises at 9 a.m. Rotate the top piece sothat the Moon is traveling across the sky above the horizon; notice that the right side of the waxingMoon as seen by the observer is illuminated by the Sun.The user should notice that during a given night, as the Moon and Sun cross the sky from east to west,the phase remains the same throughout the night. In other words, the angle between the Sun and Moon45° for crescent, 90° for quarter, and 135° for gibbous, is constant throughout the night as the Earth rotatesunderneath the distant Sun, Moon, and stars.
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