ASTR 110                                                                                                                                                                                             Name:                            

Fall 2009

Moon Phases Observing — “Alt-Az” Chart


Plot the Moon’s position at least 6 times between New Moon and Full Moon on this “altitude-azimuth” chart.  This chart faces south, and portrays slightly more than half of the sky.  Draw the Moon large enough to show its phase (in the proper orientation relative to the horizon!), but small enough that it will not crowd out the next observation.  Label each position with its date and time. 

Notes: Elevation: 0˚ is on your horizon; 90˚ is directly overhead.  If you need to, you may slightly exceed the boundaries of this graph in either elevation or azimuth.  (For instance, if the Moon is north of your zenith, which can happen in the Spring, then keep your azimuth south-facing and keep counting “elevation” past 90˚.)  Do not worry about measuring your elevation more accurately than approx. 5˚, or your azimuth more accurately than approx. 1/16 of the compass (“WSW” or “ESE”, for instance). 


Important: Each observation MUST be made at roughly the SAME TIME OF NIGHT for this chart.  Choose a time of night in the mid-evening (between 7:00 and 8:30 p.m. is good), and then make all of your observations at approximately the same time (plus or minus approx. 15 minutes).