Every bride knows the scene. The proposal has barely happened and someone is already asking for the date, and the date never comes alone: it cannot fall on a public holiday, August is out because grandmother says it is bad luck, it has to be a Saturday when the church and the venue are both free. An aunt suggests the parents' wedding anniversary. The groom wants 12/12, because it looks nice on the invitation.

It is the same with a company. The launch goes on the 1st, to start on a round number, and the owner spends the week before checking the weather forecast as if it decided the shop's future. The shop opens on a Friday, to catch the weekend. The contract waits until after Carnival, because before that nobody answers messages. Choosing the date for a beginning is one of the oldest gestures there is, and almost no one does it by chance.

Astrology has a whole technique dedicated to this choice, far older than the calendar at the registry office. The idea behind it is simple: everything that begins has a sky, and the sky of the instant something is born says something about what was born.

You have a birth chart because you were born at an instant, in a place. Electional astrology applies the same logic to an event: the chart for the moment is the birth chart of the thing that is beginning. Signing the contract, saying yes at the registry office, the shop door opening for the first time.

The difference is that, with a person, the sky is simply given. With an event, part of it is chosen. Nobody changes the whole sky; the instant, yes. Among the dates and times your life allows, the election looks for the one with the structure that best serves what you want to begin.

And each beginning asks for its own sky. A wedding wants one thing, a surgery wants another, a haircut wants a third. A date good for opening a company can be dreadful for ending a partnership. That is why the useful question always carries the goal along with it: what is the good day for this, in this city, in this period.

Seen this way, every beginning also gains an image. A business born with the Ascendant in Taurus carries the figure of someone who builds slowly and holds on; one born in Gemini, that of someone who moves around and talks. The image never promises what will happen. It gives the chosen day a meaning the person carries with her, and many people say that is what made the date unforgettable.

If there is one point the electional tradition looks at before all others, it is the Moon. It is the fastest body in the sky, changing sign every two and a half days, and in beginnings it describes how things unfold after the start. The phase matters: the waxing Moon supports what you want to see grow, the waning Moon what you want to see shrink. That is why there is a lunar calendar for hair, and that is why the phases of the Moon are the first thing anyone learns about the subject.

The sign it sits in also matters, along with the aspects it will make in the hours that follow. In a wedding election, a Moon moving toward a good aspect with Venus is the image of something coming together. A Moon moving toward a square with Mars calls for attention, and sometimes waiting one more hour settles it.

And there is the Moon void of course. It is the stretch, which can last minutes or almost a day, in which the Moon has already made its last aspect within a sign and has not yet entered the next one. Tradition says what starts in that window tends not to turn out as expected: the meeting that ends with no decision, the purchase that goes back to the shop.

For nearly every beginning it is a stretch to avoid. For some, like a procedure meant to push something away or bring it to a close, tradition treats it differently. This kind of detail is what separates an election from a table.

Everyone has heard that you should not sign anything with Mercury retrograde. The rule has some ground to it: Mercury answers for contracts, papers, messages and travel, and when it appears to move backward in the sky, tradition links the period to reviews, delays and things that need to be redone. The dates, and what actually changes during those weeks, are in Mercury retrograde.

In an election, it carries weight depending on the goal. For signing a contract, launching a website or sitting an exam, Mercury retrograde counts for a lot. For a wedding, what carries weight is Venus, and a retrograde Venus in the period can strike whole weeks off the list. For a surgery, what counts are the Moon and the part of the body being operated on.

No single factor decides a date on its own. The election weighs dozens of criteria at once, and a day with one small flaw and five strong qualities usually beats a day with no flaw and nothing in its favour either. It is the opposite of the list of bans that circulates online, where a single retrograde planet condemns the whole month.

In practice, this takes a weight off whoever is planning. If your registry office only has an opening during a week of Mercury retrograde, the useful question becomes “what is the best time within that week, and what do I do to make up for it?”. Reread the contract twice, confirm in writing what was agreed verbally, arrive early. Simple precautions, worth taking any week.

Every goal has a house in the chart. The wedding belongs to house 7, the one for partnerships; money, to house 2; the opening of a business that goes public, to house 10. The planet that rules the sign on that house, in the chart for the moment, becomes the significator of what is being born, and the election looks for it to be strong, well placed and free of heavy aspects.

This is where the Ascendant of the instant comes in. It changes sign roughly every two hours, and it is what decides which sign occupies each house. That is why the time matters just as much as the day: at ten in the morning and at two in the afternoon on the same Saturday, the wedding has two different charts, with different rulers and different points needing attention.

That is why the city matters too. The same instant has different Ascendants in São Paulo and in Lisbon, and an election made for one city does not work for another. A list of good dates for a whole country, however good the intention behind it, can only look at what is the same for everyone, which is basically the Moon.

An example helps show the difference. Two friends each want to open her own studio on the same Saturday, one in Belo Horizonte and the other in Porto Alegre. The Moon is the same for both. The Ascendant and the rulers of the houses are not, and the best hour for one can be the worst hour for the other.

The list of beginnings that can be elected is long. A marriage proposal, an engagement, the registry office. Opening a company, launching a product, signing a contract, moving house. A job interview, a thesis defence, a trip, the arrival of an adopted pet. Cutting your hair, getting a tattoo. There are more than three hundred goals, and each has its own rules.

Some goals come with very narrow criteria. A planetary talisman requires the planet strong, well placed and at a specific hour, and there are planets that go years without offering an hour like that; the astrological magic tells that story in detail. At the other end, a haircut accepts almost any week, as long as the Moon is in the right phase and the time helps.

What is needed to make an election is whatever your life allows: the city, the period the date can fall within and, if you like, the days of the week and possible times. Whoever can only marry on a Saturday afternoon says so, and the search respects it. It sweeps the period hour by hour and returns the best options, each with what it favours and what calls for attention.

If no hour in the period reaches a good rating, that is said plainly from the start. Sometimes the most useful thing an election tells you is that the month you chose is weak for that purpose.

An elected date does not guarantee an outcome. The wedding set for the best sky of the half-year still depends on the couple; the company opened at the right hour still depends on the product, the cash flow and a great deal of work. The date chooses the ground, and you are the one who plants. An honest reading uses phrases like “the configuration favours” and never promises success, profit, pregnancy or cure.

In matters of health, order comes before everything: surgery is scheduled by the doctor first. The election only compares dates the medical team has already offered as possible, and emergency surgery is not elected, it is done when needed. No sky justifies putting off an indicated procedure.

The same goes for court deadlines, which the lawyer decides, and for money decisions, where the election only looks at the timing of a choice that is already yours, without assessing risk or promising a return.

And the election does not hide flaws either. The best option in a period almost always has some weak point, and a good reading says so, just as clearly as it says what is in its favour. Whoever chooses needs to know what she agreed to give up.

Electional astrology is among the oldest practices in astrology. The Greeks called it katarchai, beginnings, and Dorotheus of Sidon, who wrote in verse in the first century, dedicated a whole book to it: when to build, when to buy, when to travel, when to marry.

In 762, according to the chronicles, the caliph al-Mansur asked the court astrologers for the moment to lay the foundation of Baghdad, and Masha'allah, one of the most cited names in medieval astrology, was among them. Eight centuries later, in England, John Dee was consulted to set the day for Elizabeth I's coronation, in January 1559.

None of them had a computer. They calculated by hand, with tables, and so they compared few dates. Today you can sweep through every hour of a period of months and measure each one against dozens of criteria, and the gesture is still the bride's with the calendar in hand: looking at the start with care, because the start stays.

Next time someone in the family asks for the date, try turning the question back: what do you want to be born on that day? The answer usually says more about the right date than the calendar does.

And the questions that come up most on this subject, with the short answer: