Astronomical
A live countdown to the next new moon — the point in the lunar cycle when the moon is darkest and least visible.
This uses the same known-reference-new-moon method as the Moon Phase Calculator — counting days since a confirmed new moon and dividing by the average 29.53-day synodic month to project the next one forward. It's accurate to within roughly a day, which is fine for planning but not for professional astronomy.
With no moonlight washing out the sky, a new moon is when faint stars, the Milky Way, and meteor showers are easiest to see — the opposite of a full moon, which is the worst time for that kind of viewing.
Related
The full phase breakdown for any date.
The opposite point in the same cycle.
The next calendar month with two full moons.