Moon void-of-course is a time when plans and expectations tend to go awry. Purchases made during this time may be for articles that are never used, meetings that occur during this time are often unproductive, and spells that are cast during this time manifest in unexpected ways.
To understand moon void-of-course, we need to first be clear about two things: zodiac signs and moon aspects. In Western astrology, the sky from our perspective on earth is divided into twelve equal portions. These are the twelve signs of Aries, Taurus, Gemini, etc. An aspect is a relationship between two planets, again from our perspective here on earth. The full moon, when (from our perspective) the moon is opposite the sun, is an aspect. The new moon, when from our perspective the sun and moon are aligned, is another aspect. When from our earth perspective the moon overshadows the sun, this is an aspect we call a solar eclipse. What we call the major aspects are conjunctions, oppositions, squares, trines, and sextiles. Conjunctions are lined up (0°), oppositions are 180°, squares are 90° angles between planets (again, looking at the sky from Earth), trines are 120°, and sextiles are 60°. Moon aspects don’t just involve the sun, but can involve other planets (Mercury, Venus, Mars, etc.).
Void-of-course starts when the moon makes its last major aspect in a particular sign and lasts until the moon enters the next sign. To give an example, if the moon while in the sign of Pisces makes aspects that are opposite the sun, then square Venus, and finally sextile Mars – and then the moon makes no other major aspect until it moves into the sign of Aries – the moon is void-of-course during the time between the sextile with Mars and the moon’s entry into Aries. This period of time could be two minutes or two days, depending on how the planets are aligned.
So now that I’ve explained it, there’s a good chance you don’t believe it. When the concept of moon void-of-course was first introduced in the seventeenth century, astrologers chuckled and put the concept away, and it had very few adherents until the mid-twentieth century, when an astrologer named Al Morrison began campaigning doggedly for others to take the phenomenon seriously. And it turns out that moon void-of-course times do have an effect on human affairs. Yes, it’s screwy and it makes no sense. Ignore it at your peril.
My upcoming class Mastering Moon Energies will discuss the impact of void-of-course moon on spellcasting.