New moon western horizon shortly after sunset and before moonset. A lunation or synodic month is the average time from one new moon to the next. In the J2000.0 epoch, the average length of a lunation is 29.530588 days (or 29 days, 12 hours, 44 minutes, and 2.8 seconds). However, the length of any one synodic month can vary from 29.26 to 29.80 days due to the perturbing effects of the Sun's gravity on the Moon's eccentric orbit. In a lunar calendar, each month corresponds to a lunation. Each lunar cycle can be assigned a unique lunation number to identify it. The
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