This image created by Alan Dyer of Silver City, New Mexico
The full Moon of March 5th will be as much as 50,000 km farther away than other full Moons of the year, making it smaller and dimmer than usual.
The apparent size of the Full Moon changes throughout the year because the Moon’s orbit is not a circle, it is an ellipse, with one side (apogee) 50,000 km farther from Earth than the other side (perigee): diagram. When the Moon is on the apogee side, it looks smaller and dimmer in proportion to its increased distance.
Can you tell the difference? Some people say “yes,” others “no.” There are no rulers floating in the sky to measure lunar diameters. Without a reference, it can be challenging to distinguish an apogee Moon from a perigee Moon. Decide for yourself. Go outside after sunset on March 5th, look east, and enjoy the mini-moonlight.