There's Moonlight ... When??

It happened again last night.

I'm sitting on the couch, playing Spider Solitaire and watching a perfectly good movie.  The characters are settling into their bedrolls after the evening meal on the trail drive, but first they must notice the moon and discuss it.  Sure, it looks pretty, a nice, bright crescent on the horizon.  It's worth looking at.  Only problem is, the director has shot a fourth quarter moon, which rises in the east just before sunrise.  A fourth quarter moon is distinctive by its east (or left) side being lit up, as the sun is shining on it from below that horizon, about to make its appearance.

For some reason, the moon, as a focal point in books and movies, seems to have a mind of its own.  In the wrong hands, it's full one night, a sliver the next.  Or the villain is anticipating a new moon tomorrow (he plans to use the dark of night for some nefarious scheme), but right now it's glowing overhead, as bright as a fire at midnight!

Is this Hollywood's fault?  They've been playing fast and loose with this for years, and we probably see movies more often than we step outside and take note of where the moon is, where it was last night and the night before.

Some brief pointers for your writing:

A full moon and new moon are two weeks apart.  You can't play with this.  If your lovers are meeting one night under a full moon, and you need your villain prowling around beneath a dark sky, you either have to:

When God said, "Let there be light,"
He didn't mean authors could do it at will!

A famous author wrote about a sliver of moonlight one night, a bright "half moon" the next. Again, this is as impossible as having the sun set at 8 o'clock one evening and 2 o'clock the next. How can you avoid similar mistakes? Read through the cycle below. Then, if you don't leave here with a new understanding of the Moon's cycle, bookmark it and come back whenever you're plotting night scenes.

Let's start at the beginning. Please remember that you cannot skip around. Day 1 is followed by Day 2, and so on. If you need a dark night during a "visible moon" period, remember cloud cover!

Day 1: New Moon
The Sun and Moon are conjunct. They rise and set together.

- Moon is not visible. No moonlight. Period.

Day 2: waxing Moon follows the sun across the sky
- a tiny sliver of Moon is visible near the Sun
Days 3-7: the Moon lags farther behind (east of) the Sun
- the illuminated crescent expands daily, and can be seen longer each evening after sunset

Day 8: 1st quarter Moon, approx. 6 hours behind the Sun
- rises around noon
- overhead around sunset
- moonlight ends at midnight as the moon sets

Day 9-14: waxing gibbous Moon

- rises in the afternoon, later each day
- sets after midnight, later each night
- moonlight lasts longer each night

Day 15: Full Moon, the midpoint of the cycle
- visible all night
- rises as the sun sets
- overhead at midnight
- sets as the sun rises (can't see it during the day)

Day 16-22: waning gibbous Moon

- rises later each evening, giving you a dark period from sunset to moonrise, and that period is longer each night
- sets later each morning

Day 23: 3rd quarter Moon
- dark from sunset to midnight
- moonlight from midnight to noon
- rises around midnight

- overhead around sunrise

- sets around noon

Days 24-28: waning crescent Moon
- rises later each night (technically later each morning, as it's after midnight)
- less light for less time each night as the lighted area decreases in size

Day 29:
- finally, a tiny sliver of Moon is visible in the east for only a short time before sunrise