On the Autumnal Equinox, you see the Moon in the Waxing Crescent Phase at an angle of 45 degrees above the western horizon. What is the approximate local time?
Can someone please explain how to obtain the answer? Thank you!
To determine the approximate local time based on the Moon's phase and angle above the horizon, you will need to consider a few factors: the phase of the Moon, its position in the sky, and the time of sunset on the Autumnal Equinox.
1. Determine the phase of the Moon: The Waxing Crescent Phase is the phase of the Moon that occurs after the New Moon phase. It is a small sliver of the Moon's illuminated side visible from Earth.
2. Understand the Moon's position in the sky: The angle of 45 degrees above the western horizon tells us that the Moon is positioned halfway between the western horizon and the overhead zenith (90 degrees). This means the Moon is about halfway through its trajectory across the sky from east to west.
3. Consider the time of sunset: On the Autumnal Equinox, the length of day and night are roughly equal. Therefore, sunset will occur approximately 12 hours after sunrise. Depending on your location, you can look up the exact time of sunset for your area on the Autumnal Equinox.
Now, let's put these factors together:
If we assume the Moon rises in the east at approximately the same time as sunset, then it will take about 6 hours for the Moon to reach an angle of 45 degrees above the western horizon (halfway through its trajectory).
Therefore, subtract 6 hours from the time of sunset to estimate the approximate local time when the Moon is at this angle. For example, if the time of sunset is 6:00 pm, subtracting 6 hours gives us 12:00 pm (noon) as the approximate local time when the Moon is at 45 degrees above the western horizon.
Keep in mind that this is an estimate, and the actual local time may vary depending on your location and specific circumstances.