Fullfor aninstant

[01] [THE CYCLE]

29.53

Days, on average, from one full moon to the next: the synodic month. The Moon’s uneven orbit can move a full moon up to thirteen hours either side of that average.

[02] [THE TILT]

5.145°

The Moon’s orbit is tilted this much to Earth’s, so it usually passes just above or below our shadow. Only when it crosses the line exactly do we get an eclipse, like 3 March and 28 August this year.

[03] [NO SHADOWS]

Flat

With the Sun straight behind you, crater shadows vanish. For seeing relief, look at a half moon instead: the terminator line is where the craters stand out.

[04] [OPPOSITION SURGE]

Glare

At full, the surface suddenly brightens more than its angle alone explains: the opposition surge. That light outshines many stars, which is why it is a poor night for deep-sky observing.

[05] [HALF THE WORLD]

½

For any one place, about half of all exact full moons happen in daylight, with the Moon below the horizon. The almanac date is a calendar day; check the hour for your time zone.

[06] [ECLIPSES]

~2 h

Totality in a lunar eclipse can last up to nearly two hours, and anyone on Earth’s night side can see it, unlike a solar eclipse, which only a narrow strip sees for a few minutes.