The Lunar Metonic Cycle - Tonight's Full Moon

Tonight's full moon is no usual full moon, it is the full moon with highest delcination (28.72 degrees north) the moon will make in the northern hemisphere. As we have mostly clear skies tonight, enjoy this rare phenomenon, go outside around midnight tonight and notice how shortthe shadows are. If you are thinking that you will catch the next one, don't hold your breath, it won't happen for another 19 years!

Near its northernmost declination, tonight's Full Moon will be a special one, arcing high in northern hemisphere skies. But a Full Moon won't occur on this calendar date for another 19 years, a period known as the lunar Metonic cycle. September 15th's lunar phase and date were notable too, marking the return of a gibbous Moon rising over the High Sierra mountains. - NASA