June 21, 20
The moon is at its First Quarter today. Half-lit. Bright. Just right for staring up without squinting too much.
If you check the sky tonight, roughly 54 percent of that gray face is illuminated, says NASA. Enough light to pick out some serious surface real estate.
You don’t need expensive gear. Just eyes. Look for Mares Fecunditatis, Serenitatis, and Crisium. Those are the big, dark plains that look like ancient impact scars from our orbit.
Binoculars help. Bring those out if you’ve got ’em. You’ll spot the Endymion Crater, the jagged rim of Posidonius Crater, and the smooth basin of Mare Nectaris.
Got a telescope? You’re winning the night sky lottery. Add the Linne Crater, the highlands around Descartes, and the steep escarpment of Rupes Altai to your mental list. It’s a busy moon.
When is the full blast coming?
June 29. Count the days. The wait is short.
So what actually causes these shape-shifting acts?
It’s not magic. It’s geometry.
NASA puts the orbit cycle at about 29.53 days. Eight recognized phases in that span. The same side always faces Earth—locked in place by tidal forces—but the sun’s angle changes.
The part of the moon lit up changes as it orbits us. That’s why it goes from invisible to brilliant to invisible again. A repeating loop. We call it the lunar cycle.
Here’s how the parade breaks down.
- New Moon — Hidden. Between Earth and the sun. We see the dark side.
- Waxing Crescent — A sliver appears. Right side (if you’re north).
- First Quarter — Half-lit right. The half-moon look everyone knows.
- Waxing Gibbous — Almost full. Just a sliver missing.
- Full Moon — Bright. Fully visible. Hard to ignore.
- Waning Gibbous — Losing light on the right. The party winds down.
- Third Quarter — Half-lit, but left side. The other half.
- Waning Crescent — Fading out. Just a curve of light left.
Then back to new. Repeat.
We keep looking up because it changes every night.
“While the same side of the Moon alwaysfaces our planet, the amountof its surface lit by the Sun changes.”
It’s predictable. But never boring.
June 21 is just the middle act. The curtain rises again on June 29 when everything lights up completely. Until then, check your skies. Maybe find a crater. Or maybe just stare at the half-circle hanging above your house.
It doesn’t care if you know what phase it’s in. It just keeps spinning. 🌙
