The synodic month (full moon to full moon) averages 29.53 days, while the anomalistic month (perigee to perigee) is 27.55 days, so the phases drift with respect to perigee.
see: http://www.treasure-troves.com/astro/AnomalisticMonth.html
The synodic month (full moon to full moon) averages 29.53 days, while the anomalistic month (perigee to perigee) is 27.55 days, so the phases drift with respect to perigee.
see: http://www.treasure-troves.com/astro/AnomalisticMonth.html