The autumnal equinox in the northern hemisphere occurs each year around September 22nd when it is commonly believed that the Sun sets at the North Pole, rises at the South Pole, and night and day are of equal length everywhere on the Earth. However, this is not exactly what occurs. Almanacs show that there are actually more than 12 hours of daylight and the exact amount depends on latitude. This fact seems to belie the term “equinox,” which suggests equal night and day. The maximum extent of this phenomenon, which will be studied in this chapter, occurs directly at the North Pole. The autumnal equinox of the year 2025 occurred at 12:44 UTC (Coordinated Universal Time) on September 22nd, but the top rim of the Sun did not set at the North Pole until 15:52 UTC on September 24th, which is approximately a period of 2.13 days. The analysis of this phenomenon would normally employ spherical trigonometry; however, simple planar trigonometry and analytic geometry will be used to obtain approximations that are in error by less than \(0.3\%\) . The approach is unique and nonstandard, being designed to enable the uninitiated to gain insight into an interesting and relatively unknown physical phenomenon without requiring an extensive knowledge of the rather esoteric nomenclature of astronomy.