Lunar occultation

In the evening of Sunday, 4 May 2014, the waxing crescent Moon will occult (hide) the bright star Lambda Geminorum in the constellation Gemini, the Twins. The 3.6-magnitude star will disappear at the Moon’s east limb (edge) at 10:39 p.m. Central European Summer Time (CEST) at position angle 70°.

It will reappear at the west limb at 11:28 p.m. CEST, position angle 321°. Position angle is the angle of the star, measured to the east (anticlockwise) from the northernmost point of the Moon’s limb.


A useful and interesting exercise is to note the exact time of the occultation. Use steady binoculars or a telescope to view the Moon and this star, starting a few minutes before 10.39p.m.  Synchronize your watch against the time applet on the right hand sidebar at  To find the exact time, use a stopwatch and start it when the star is covered (whilst looking at the event through the eyepiece). Now you may stop the watch at the next turn of a minute. The time of the start of the event may be calculated by subtracting the stopwatch time from the time at which the stopwatch was stopped.

Send us your event timings at