September 2030

About five datable events a week

An astrology calendar can look sparse or overwhelming depending on what it counts, so it is worth stating the size of the thing. Counting a full year of the sky: 161 Moon sign changes, 50 planetary sign changes, 21 stations where a planet turns retrograde or direct, and 25 lunations.

That is about 257 datable events in a year — roughly five a week — and it does not include a single aspect. Add the exact aspects between planets and the count multiplies several times over. The station count varies more than the rest: 21 in the year measured here, against a thirty-year average of about 18.

So a calendar is always a selection. The question is not whether something is happening today but whether what is happening is slow enough to matter, and that is the filter this page applies rather than listing everything the ephemeris can produce.

What the yearly totals look like broken down

The planetary ingresses distribute exactly as their speeds predict. In the year measured, Mercury changed sign 14 times, the Sun and Venus 12 each, Mars 6, and Jupiter, Saturn, Uranus and Neptune once each. Pluto managed 2, which happens when a planet crosses a sign boundary and then retrogrades back over it.

The stations are more even: two each for every planet except Mercury, which had 7 in that particular year. Every retrograde needs two stations, one to turn back and one to turn forward, so the count is simply twice the number of retrograde periods — and over thirty years the long-run average works out at about 18 a year rather than the 21 this particular year happened to hold.

Lunations come to 25 in a year — twelve or thirteen new Moons and twelve or thirteen full Moons — because the synodic month is 29.53 days and a year holds 12.37 of them. That fractional part is why a thirteenth full Moon appears in some calendar years and not others.

Which entries are worth acting on

The honest ranking is by duration. A Moon sign change describes about two and a quarter days and applies to everyone alive; a Jupiter or Saturn ingress describes a year or two and still applies to everyone, but it moves the same slow planet through a whole house of your chart.

The entries that are personal are the ones that touch your own degrees. A Venus ingress into Libra is a general flavour; a Venus ingress into the sign holding your natal Sun is a contact, and the calendar only becomes a personal document when it is read against a chart.

Retrograde stations deserve a note. The station itself is the point where a planet is moving slowest and sitting on one degree for days, which is why the tradition treats the station degree as more significant than the retrograde period as a whole.

Void-of-course entries, and how to weigh them

Most calendars including this one mark void-of-course Moon periods: the stretch between the Moon's last major aspect in a sign and its entry into the next. They are the most numerous entries on any lunar calendar and the most misread.

Measured across ten years, void periods cover 14.6 per cent of all elapsed time — about one hour in seven, in roughly 160 separate periods a year. A rule that forbids starting anything during one is asking for a seventh of a life to be scheduled around.

The classical claim was narrower: in horary astrology, a question asked under a void Moon was read as coming to nothing. That is a statement about a question rather than about an afternoon, and the extension into general advice happened much later and with much less support.

How to use a month at a glance

Read the ingresses of the slow planets first, because there will be at most one or two in a month and they set the background for everything else.

Then find the two lunations. A new Moon and a full Moon in a month give the rhythm, and the sign each falls in tells you which pair of houses in your own chart is being lit.

Then use the Moon table for texture rather than for decisions. Knowing that the Moon enters Scorpio on Thursday afternoon is useful for understanding why Thursday afternoon feels different from Thursday morning, and it is not a reason to move an appointment.

What a calendar cannot do

It is not personal until it meets a chart. Every entry here is the same for everyone alive, so a calendar describes the sky and not a person.

It does not rank events by importance for you. A calendar can only sort by date; whether an entry matters depends on your natal degrees, which the calendar does not know.

And it cannot make a case for acting on any single entry. Around 257 events a year, five a week, means something is always happening — and a system where something is always happening cannot also be a system where each thing is significant.