Because the Moon's orbit is elliptical (eccentricity ~0.0549), its apparent size varies. When the Moon is near apogee (farthest: ~405,500 km), its umbral shadow cone expires before reaching Earth. Observers on Earth see an Annular Eclipse ("Ring of Fire") where the Sun's bright rim remains visible.
During a Total Lunar Eclipse, Earth sits directly between the Sun and Full Moon. Earth blocks all direct sunlight, but sunlight filtered through Earth's atmospheric ring undergoes Rayleigh scattering—bending red wavelengths into the umbra to cast a coppery red glow.
Because the Moon's nodes regress westward over 18.6 years, eclipse seasons repeat roughly every 6 months (173.3 days). The Saros cycle of 18 years, 11 days, 8 hours harmonizes the synodic, anomalistic, and draconic months to produce near-identical eclipse geometries.