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
STS-74 was performed on orbit 128 at around 11:00 am EST (16:00 UTC), leading to a landing at Kennedy Space Center (KSC), Florida, on Runway 33 of the Shuttle Landing Facility. The main landing gear touched down at 12:01:27 pm EST (17:01:27 UTC) on 20 November, a mission elapsed time (MET) of 8 days 4 hours 30 minutes and 44 seconds. Nose gear touched down at 8 days 4 hours 30 minutes 54 seconds (12:01:37 pm EST – 17:01:37 UTC) and "Atlantis"'s wheels stopped at an MET of 8 days 4 hours 31 minutes 42 seconds (12:02:24 pm EST – 17:02:24