Lunastices

A lunar standstill occurs when the Moon’s declination reaches extreme positions during its 18.6-year cycle. There are two types: major standstills, when the Moon reaches a declination of up to ±28.7°, and minor standstills, when it stays within ±18.1°. During major standstills, the Moon’s rising and setting positions reach their northernmost and southernmost points on the horizon. These shifts have a significant impact on tidal forces due to the varying gravitational pull of the Moon, which affects ocean tides and Earth’s crust.

The Moon’s orbit is tilted relative to Earth’s equator, causing these changes in declination. During a major lunar standstill, the Moon’s apparent movement across the sky becomes more extreme, rising and setting far north or south, while during a minor standstill, its movement is less dramatic. This cycle directly influences the Moon’s visibility at different latitudes, with its zenith position varying significantly. Such shifts are observable across the world.

• Patrick Hartigan article on Lunar Standstills

• Griffith Observatory article on Lunar Standstills for 2024 and 2025