The void-of-course Moon, explained

As the Moon travels through a sign (about 12 to 15 degrees a day), it forms aspects with the planets: exact angles measured along the zodiac. The five major aspects are the conjunction (0 degrees), the sextile (60), the square (90), the trine (120) and the opposition (180).

Once the Moon has completed its last exact major aspect in a sign, it has nothing left to "meet" until it crosses into the next sign. From that last aspect until the sign change, the Moon is said to be void of course. The moment it enters the new sign, the void ends.

Aspects that are already separating do not count. What matters is the last aspect that becomes exact while the Moon is still in the sign.

Traditional astrology, as written down by authors such as William Lilly in the seventeenth century, counted only the planets visible to the naked eye: the Sun, Mercury, Venus, Mars, Jupiter and Saturn.

Most modern calendars also count Uranus, Neptune and Pluto. With more planets to meet, the Moon tends to stay in contact longer, so modern void periods are often shorter than classical ones. Because the two methods differ, two calendars can list slightly different times for the same void, and neither is wrong: they answer the question with a different set of planets.

The Orbela app uses the modern set, the Sun through Pluto, the same approach used by most published void-of-course tables.

The classic saying about the void Moon is that "nothing will come of the matter": plans begun during a void period are said to fade, change course or end differently than intended. Lilly added that the Moon performs somewhat better when void in Taurus, Cancer, Sagittarius and Pisces.

Astrologers who follow the idea tend to use void periods for activities where an outcome is not the point:

If you can choose the timing, the tradition suggests waiting for the Moon to enter its next sign before:

Void periods happen roughly every two days, so treating each one as a stop sign would make daily life impossible. Many astrologers use it as a light tiebreaker: when you already have the freedom to pick a time, pick one outside the void. When you do not, carry on.

Also keep time zones in mind. A void that starts late at night in one city starts the next morning in another, so always read the times in your own zone.

On the Today tab of the Orbela app, the "Moon void of course" card tells you whether a void period is happening now, or when the next one starts and ends, in your phone's own time zone. The times are computed on your device from the planetary positions, using the modern set of planets described above.