Why does the date of a named full moon generally shift earlier by about 11 days each year?
Answer
The average length of the full moon cycle (synodic month) is about 29.5 days.
The full moon cycle, known as the synodic month, averages about 29.5 days, causing the date of any named full moon to shift earlier by about 11 days each year until certain orbital mechanics force a jump.
Related Questions
What primarily defines the Harvest Moon astronomically?How is the Hunter's Moon defined relative to the Harvest Moon?During which months can the Harvest Moon technically occur?If the Harvest Moon is typically in October, what month is the Hunter's Moon usually associated with?What was the primary historical benefit of the Harvest Moon for Northern Hemisphere farmers?Why did the bright light of the Hunter's Moon benefit hunters?What is the fundamental difference between the definitions of the two moons?What is the inclusive date range during which the Harvest Moon must fall?The unusually short interval between moonrises around the Harvest Moon is related to what astronomical feature?For which full moon phase would deep-sky photography likely present the greatest challenge due to lingering light?Why does the date of a named full moon generally shift earlier by about 11 days each year?