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
Riverside Beaver County School District and administrators with an average teacher salary of $57,898 and a top salary of $112,815. The work year is 186 days with 180 student instruction days. Teachers work 7 hours 45 minutes with a 30-minute duty-free lunch and a daily preparation period. Teachers receive extra pay for extra required work like updating curriculum. Additionally, the teachers receive a defined benefit pension, health insurance, professional development reimbursement, 3 paid personal days, 10 paid sick days (which accumulate) vision insurance, dental insurance and many other benefits. Guidance counselors receive extra $400 pay plus extra summer pay. In 2011, the average teacher salary