Lunar month circular, the speed of Earth's progression around the Sun varies during the year. Thus, the angular rate is faster nearer periapsis and slower near apoapsis. The same is so for the Moon's orbit around the Earth. Because of these variations in angular rate, the actual time between lunations may vary from about 29.18 to about 29.93 days. The long-term average duration is days (29 d 12 h 44 min 2.8016 s). The synodic month is used to calculate eclipse cycles. It is customary to specify positions of celestial bodies with respect to the vernal equinox. Because of Earth's precession of
March 1997 lunar eclipse the third of four lunar year eclipses at the descending node of the moon's orbit. The lunar year series repeats after 12 lunations or 354 days (Shifting back about 10 days in sequential years). Because of the date shift, the Earth's shadow will be about 11 degrees west in sequential events. March 1997 lunar eclipse A partial lunar eclipse took place on March 24, 1997, the first of two lunar eclipses in 1997. This partial lunar eclipse was nearly total; however, it occurred 3 days after the lunar apogee, so the umbral shadow is smaller. This is the 29th member