Which quarter phase is characterized by the right half of the Moon being illuminated as viewed from Earth?

Which quarter phase is characterized by the right half of the Moon being illuminated as viewed from Earth?

• A. First Quarter
• B. Full Moon
• C. Last Quarter
• D. New Moon

Answer: (A)

During the first quarter phase, the Moon has completed about a quarter of its orbit around Earth, and sunlight is hitting the Moon from the right side as seen from the Northern Hemisphere. This causes the right half of the Moon’s near side to be illuminated while the left is dark, so the Moon appears as a half-circle with the bright right side. In contrast, the last quarter shows the left half lit, the full Moon has the entire near side illuminated, and the New Moon is dark. (In the Southern Hemisphere, the illuminated side would appear on the opposite side due to perspective.)

During the first quarter phase, the Moon has completed about a quarter of its orbit around Earth, and sunlight is hitting the Moon from the right side as seen from the Northern Hemisphere. This causes the right half of the Moon’s near side to be illuminated while the left is dark, so the Moon appears as a half-circle with the bright right side. In contrast, the last quarter shows the left half lit, the full Moon has the entire near side illuminated, and the New Moon is dark. (In the Southern Hemisphere, the illuminated side would appear on the opposite side due to perspective.)