What the reading is made from
Two things, and nothing else: the sky as it genuinely stood at the moment you were born, and forty short readings written in advance — one for each planet on each of the four angles. Nothing is composed on the spot. The same birth moment gives you the same words today, next year, and on someone else’s screen.
That is a promise about steadiness rather than about cleverness. A reading that changes each time you look at it was never telling you anything about a place.
Where a line stops
A planet’s rising and setting lines curve away toward the poles, and past a certain latitude they simply stop — up there the planet never rises or sets at all, so there is no line to draw. We end the arc exactly where it truly ends. Slow outer planets sometimes stop in the middle latitudes, and you will see their arcs finish there rather than continue as a comforting fiction.
How close is close
The distance from a place to one of your lines is measured as real ground — 111,319.9 metres to the degree, the same width everywhere on earth, whether the city is in Ecuador or Iceland.
⚠️ Where our figures differ from older software
Some long-established astrocartography programs measure the distance to an overhead line in longitude instead. The two agree near the equator and drift apart toward the poles, because a degree of longitude narrows as you go north or south — at 60° it is only about 56 km, against 111 km of true ground.
So a city one longitude-degree from your overhead line reads as roughly half that with us, at 60°N. Neither figure is wrong. Ours describes a constant distance you could actually walk, which we think is the more useful thing to know when you are deciding where to live — and we would far rather you read it here than discover it later and assume something is broken.
When several lines reach the same place
Most cities are touched by more than one. We sort them by how close they run, weigh the near ones more heavily than the distant ones, and give you a single reading rather than three paragraphs arguing with each other. Where two lines genuinely pull against one another — drive against rest, expansion under constraint — we name the tension instead of averaging it into something bland.
Any suggestion about how long to stay always takes the strictest of every line reaching that place, never the closest one. A generous city that also sits on a demanding line inherits the demanding ceiling.
The hour you were born, and what we will not claim
Four minutes moves a line about a hundred kilometres. That is the whole difference between a city sitting on your line and sitting nowhere near it — so we ask how sure you are, and we change both what we work out and what we are willing to say:
| What you know | What we give you |
|---|---|
| The hour, to the minute | Full precision, exact distances, and plain language about a direct hit |
| Roughly — within half an hour | Wider readings, named as regions, and no claim of a direct hit at all |
| Not at all | No lines. Your planetary signs and the sky as it moves now, which do not depend on the hour and stay exact |
What we will never do
🌿 Our commitments
- Draw a line we cannot place honestly.
- Tell you a place is good without telling you what it asks in return. Every one of the forty readings carries both halves.
- Find meaning in every city. When nothing of yours runs nearby, we say the ground is quiet and leave the space empty.
- Speak about your health. This is a companion for choosing where to be, not guidance about your body or your mind.
The workings, in full
For anyone who would like to check us. Nothing new is claimed below; it is the same page in the older language.
Positions, lines, and where they end
For your birth instant we take the geocentric apparent right ascension (α) and declination (δ) of ten bodies, together with Greenwich Apparent Sidereal Time (θ₀). Positions come from a JPL-derived ephemeris accurate to well under an arcminute — far finer than any distance this product reports, so the sky is never the limiting factor. Your birth time almost always is.
Midheaven and Imum Coeli lines are meridians:
Longitude_MC = α − θ₀
Longitude_IC = (Longitude_MC ± 180°) mod 360°
Ascendant and Descendant lines are horizon curves; for each latitude φ:
cos H = −tan φ · tan δ
Longitude_AC = α − H − θ₀
Longitude_DC = α + H − θ₀
That equation only has a solution while |tan φ · tan δ| ≤ 1. Beyond it the body is circumpolar and the line does not exist. We end the arc at the boundary latitude rather than forcing the value back into range, which would draw a line where there is none.
Orb is great-circle degrees: geodesic metres ÷ 111,319.9.
The geometry, drawn
LocalAstro is a lifestyle and planning companion. It offers astrological perspective on place and timing — not medical, psychological, financial, or legal advice.