Choosing a date: the basics of electional astrology

By Rhys Calloway

Astrologers choose a date by casting charts forward in time and picking the moment whose chart best suits the thing being started. The Moon carries most of the weight: what sign it is in, what it aspects next, and whether it is void of course. After that, the ruler of the matter, and the angles of the chart. Most of the work is done by three or four rules.

How do astrologers choose a good date?

The method is subtraction. You take a range of possible dates, apply a short list of disqualifying conditions, and see what survives. What survives is the election.

The conditions most electional astrologers apply, in roughly the order they apply them:

Condition	What it means	Why it disqualifies
Moon void of course	The Moon will make no more major aspects before it leaves its current sign	Traditionally read as "nothing will come of it" — the matter drifts
Moon's next aspect	The next major aspect the Moon perfects	Held to describe how the matter turns out
Ruler of the matter afflicted	The planet governing the subject is retrograde, combust, or badly placed	The thing itself is compromised, not just its timing
The angles	Which signs sit on the Ascendant and Midheaven, and what rules them	Sets the chart's whole condition
Mercury retrograde	Mercury moving backwards from Earth's view, about three weeks, three times a year	Contested. See below

That is the shape of it. Everything else is refinement.

What is electional astrology?

Electional astrology is the practice of choosing the moment to begin something, using the chart of that moment. The word comes from the Latin electio, a choosing. It is the mirror image of natal astrology: instead of reading a chart you were handed, you select the chart you want.

It is old. The technique appears in Dorotheus of Sidon, writing in verse in the first century AD, whose fifth book is almost entirely elections — when to build, when to marry, when to buy, when to sail. Māshā'allāh and Sahl ibn Bishr carried it into the Arabic tradition in the eighth and ninth centuries. William Lilly's Christian Astrology, published in London in 1647, gives elections comparatively short treatment but assumes the reader knows the form.

The branch is less mystical than the others for a structural reason. An election makes a claim you can check. You picked a date, you used it, and something happened or it did not. Natal interpretation can absorb almost any outcome. An election that fails is harder to talk your way out of.

What do people actually elect for?

Weddings, business openings, contract signings, surgery dates, house moves, court filings, launches of any kind. In the historical material: voyages, sowing, building, buying livestock, war.

The common thread is a discrete beginning with a fixed start time that someone controls. Electional astrology has nothing to offer for things that do not begin at a moment. There is no election for "improving a relationship" or "being healthier". There is an election for the day you sign the lease.

A rough guide to what the tradition assigns where:

What you are electing for	What astrologers watch
Marriage	Venus, the Moon, the seventh house (partnership)
Business, opening, launch	The tenth house (career, public standing), its ruler, the Sun
Buying or selling property	The fourth house (home, land), Saturn's condition
Signing, negotiating, publishing	Mercury, the third house (communication)
Travel	The ninth house for long journeys, the third for short
Surgery	Mars, and the sign the Moon occupies relative to the part of the body

On surgery the tradition has a specific and much-repeated rule: avoid operating on the part of the body governed by the sign the Moon is in. This is the melothesic scheme, Aries to the head down to Pisces at the feet, set out in Ptolemy's Tetrabiblos in the second century and repeated more or less unchanged for fifteen hundred years. It is recorded here because it is in the tradition and because people ask. It is not medical guidance and no surgical date should be chosen on it.

Why does the Moon matter so much in an election?

The Moon moves fastest — roughly thirteen degrees a day, a full circuit in about 27.3 days — so it is the body whose position changes meaningfully within the window you are actually choosing from. If you are picking between Tuesday and Thursday, Saturn has not moved. The Moon has moved twenty-six degrees and changed sign.

Traditionally the Moon is also read as the significator of the matter's unfolding: the Sun shows the thing, the Moon shows how it goes. Its next applying aspect — the next exact angle it will form with another planet, "applying" meaning the aspect has not yet perfected — is taken as the outcome.

Hence the void-of-course rule, which is the single most used piece of electional technique and the one most likely to reach someone who knows no other astrology. A Moon is void of course when it will make no further major aspect before it changes sign. The classical reading, stated baldly by Lilly, is that nothing will come of the matter. Voids last anywhere from a few minutes to more than a day, and they occur several times a week.

Worth being exact about what the rule is not. It is not a claim that the hours are bad. It is a claim that beginnings made in them do not develop. The traditional advice for a void Moon is not to avoid acting but to avoid starting — routine work, continuation, finishing, all fine.

A note on the width of the window. Whether a Moon is void depends on which aspects you count, and astrologers differ. The strict traditional position counts only aspects to the seven visible planets, using the sign-based definition. Many modern astrologers include aspects to Uranus, Neptune and Pluto, which shortens voids considerably. Two competent astrologers can disagree by hours on the same afternoon. If an election depends on a fifteen-minute margin, the election is too tight to trust.

What about Mercury retrograde?

Mercury retrograde is a real astronomical event and a contested electional rule. Three times a year, for about three weeks, Mercury appears from Earth to move backwards against the stars. It is an artefact of the two planets' relative orbital speeds — Mercury laps us — and nothing about the planet itself changes.

The traditional objection to a retrograde planet is not superstition about gadgets. In classical doctrine a retrograde planet is weakened, and Mercury governs contracts, messages and agreements. Electing a signing under a retrograde Mercury means the significator of signing is debilitated. That is the argument, and it is internally consistent.

What the tradition does not say is that the whole three weeks is unusable for everything. Dorotheus and Lilly are concerned with retrogradation where the retrograde planet rules the matter at hand. A house move with a well-placed Moon and a sound fourth house is not obviously spoiled because Mercury happens to be retrograde three signs away.

The blanket modern version — cancel everything, back up your files — is twentieth-century popular astrology and considerably broader than anything in the source texts. Working astrologers are split on it, and have been for a century. Rulerships covers how to choose between them in practice. Sorting what a chart says from what got attached to it later is the same problem that comes up in why your horoscope is sometimes wrong.

What are planetary hours and planetary days?

Planetary hours divide daylight into twelve equal parts and darkness into twelve, and assign each part to one of the seven classical planets in a fixed rotation. Because daylight and darkness are unequal for most of the year at most latitudes, the "hours" are not sixty minutes long. In Galway in June a daylight hour runs to about eighty-five minutes; in December it is under forty.

The rotation follows the Chaldean order, slowest to fastest: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon, then back to Saturn. The first hour of each day belongs to that day's ruling planet — Sunday to the Sun, Monday to the Moon, and so on — and the sequence of days falls out of the hour sequence automatically. That is where the weekday names come from, and it is the clearest surviving trace of the system in ordinary English.

Day	Ruling planet
Sunday	Sun
Monday	Moon
Tuesday	Mars
Wednesday	Mercury
Thursday	Jupiter
Friday	Venus
Saturday	Saturn

The scheme is documented in Hellenistic and medieval sources and is standard in Arabic-language astrology. In practice it is used as a fine adjustment: having chosen the day from the Moon and the significators, you choose the hour within it. It cannot rescue a bad day.

Can an election override a birth chart?

No — and traditional astrologers are explicit about this. The election is subordinate to the nativity. An election cannot deliver something the natal chart does not support; what it can do, on the tradition's own account, is time an available thing well rather than badly.

The standard instruction, found across the medieval material, is to elect in agreement with the natal chart of the person acting: put benefic planets on angles that matter in their nativity, avoid activating the degrees their chart is sensitive to. An election made blind, without the birth chart in front of you, is a weaker piece of work than one made with it.

Which is the honest limit of the branch. Electional astrology chooses among the options a situation already contains. It does not create options.

What makes an election impossible?

Three things, and they account for most of the cases where an astrologer should decline rather than deliver.

Too narrow a window. If the date is fixed and only the hour is open, the Moon has barely moved and the angles are the only variable. Sometimes that is enough. Often the day is simply what it is, and saying so is better than dressing up a mediocre chart.

The wrong kind of subject. Elections need a start. Ongoing conditions, states of mind, other people's decisions — none of these have a moment to elect for.

Competing requirements. A wedding wants a strong Venus, a good Moon, a sound seventh house and a reasonable Ascendant, all at once, on a Saturday, in June, at a venue that is already booked. Some of those will lose. Choosing which ones lose is the actual skill, and it means ranking what the occasion is for rather than chasing a clean chart.