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
1920 Isle of Man TT 44 minutes and 6 seconds, an average speed of 51.36 mph. A mechanical retirement for Eric Williams allowed Cyril Williams also riding an AJS to build up an impressive lead of 20 minutes. However, Cyril Williams hit transmission problems at Creg-ny-Baa and free-wheeled and pushed it for the last five miles to win by a margin of 9 minutes and 50 seconds from J.A.Watson-Bourne, riding for Blackburne motorcycles in 4 hours, 37 minutes and 57 seconds, at an average race speed of 40.74 mph. The Lightweight class within Junior race was won by R.O Clarke riding a Levis and he