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PHASES OF THE MOON
The how and why of the phases of the Moon - new, crescent, quarter, full, quarter, crescent, and new again - remain some of the most challenging spatial relationships that people tend to encounter on a regular basis. The following websites have good explanations and illustrations of the process. http://aa.usno.navy.mil/AA/faq/docs/moon_phases.html http://online.bc.cc.ca.us/sea/astronomy/nakedeyeb/nakedeyc.htm http://www.astro.umd.edu/education/astro/moon/phases.html http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question3.html http://www.astro.lsa.umich.edu/Course/Labs/moon_phases/moon_phases.html A helpful synopsis of these explanations is presented in the table below. IF THE MOON IS IN THIS PHASE AT THIS TIME, THEN IT IS... new 1st qtr full last qtr --- ------- ---- -------- AT 6am, rising below setting transit AT noon, transit rising below setting AT 6pm, setting transit rising below AT midnight, below setting transit rising Remember that, just as Earth has a "sidereal day" that's 23 hours and 56 minutes (different from the "rotational day" that's just about 24 hours), the Moon has a "sidereal month" that's 27.3 days, different from the 29.5 days it takes the Moon to go through a full cycle of phases. |