How to Choose Your Chart Settings: Zodiac, House System, Node, Lilith and Orbs

Published 19 September 2026

We already have two articles explaining what the house systems are and what the orb systems do. This one answers the question people actually write in about, which is simpler and more practical. The Extended settings panel gives you four controls: Zodiac, House system, Node and Lilith, and Orb system. Out of two zodiacs, eleven house systems and nine orb standards, how do you work out which combination is yours, and how do you stop second-guessing it?

There is no test that returns a correct answer. What there is, is a sensible way to narrow the field, a way to check your shortlist against your own life, and a point at which you stop fiddling and get on with reading your chart. That is what follows.

Zodiac: the setting that changes every sign

Start here, because this control moves more of your chart than any other, and because the decision is usually quick once you know what it does.

Tropical measures the zodiac from the spring equinox, so 0 degrees of Aries is wherever the Sun sits on the first day of spring. Sidereal measures it from the fixed stars, so 0 degrees of Aries is anchored to a point in the actual constellations. Those two starting points were together around seventeen hundred years ago and have been drifting apart ever since, at roughly one degree every seventy-two years. Today the gap is about 24 degrees.

Here is Bowie's chart in both. The Fagan-Bradley sidereal zodiac is the option offered on this site.

Every single body changes sign. A Capricorn Sun becomes a Sagittarius Sun, an Aquarius Ascendant becomes a Capricorn Ascendant. For most people this is the most alarming thing they will ever do to their own chart.

Now the part that calms it down. Everything shifted by exactly the same 24 degrees, including the Ascendant and Midheaven. So the angles between the planets are untouched, which means every aspect in your chart is identical in both zodiacs. The planets also stay in the same houses, because the house framework rotated with them. The geometry of your chart does not change at all. What changes is the set of names attached to it.

Choosing one

This is a question about which tradition you are reading in, and it has no correct answer. Tropical is the basis of almost all Western astrology, and every interpretation written on this site assumes it, as does nearly every Western astrology book you are likely to pick up. Sidereal is the basis of Indian astrology and of the Western sidereal school that Fagan and Bradley founded in the 1950s.

So the practical guidance is short. If you did not arrive here with a reason to use sidereal, stay tropical, because that is the language everything around you is written in. If you already work in a sidereal tradition, or you want to compare your chart against an Indian reading, switch and stay switched. Reading tropical interpretations against sidereal placements is the one combination that produces genuine nonsense.

One practical note. The Zodiac control only appears on the four reports that can actually recast sidereally, and it works two different ways. On the natal chart it swaps you to the separate Western Sidereal Chart report and back, because those are two different pages. On Solar Return and Lunar Return it recasts the chart in place. Everywhere else on the site the control is hidden, because switching zodiac there would do nothing.

House system: start with where you were born

The zodiac decision is quick for most people. The house system is the one worth real attention, and the deciding factor is a detail most people never think to check, which is how far north or south they were born.

Placidus, Koch, Regiomontanus, Campanus and Topocentric all divide the sky using the local horizon. The further you were born from the equator, the more lopsided that division becomes. Whole Sign, Equal and Porphyrius work differently and keep their houses even wherever you were born.

Here is what that actually looks like. We took one birth moment and calculated Placidus houses for it at eight different latitudes. The planets are identical in every row. Only the house boundaries change.

Read the last column. Born in Ecuador, your Placidus houses are nearly even and the choice of system barely matters. Born in Iceland, one house swallows 103 degrees of the zodiac while another is squeezed into 7, and the choice of system changes almost everything about your chart. Above about 66.5 degrees, the polar circle, Placidus cannot be calculated at all. Astrology software does not usually stop there, it quietly substitutes Porphyrius and carries on, so anyone born in northern Scandinavia, Iceland or Alaska may have been reading a Porphyrius chart for years while the label said Placidus.

So the practical guidance is this. If you were born in the tropics, pick whichever system you like, because they will mostly agree. If you were born above about 50 degrees, which covers the UK, most of northern Europe, Canada and the northern United States, you have a real decision to make and it is worth ten minutes of your attention.

The same chart, drawn two ways

David Bowie was born in London on 8 January 1947 at 9:15 in the morning, at 51 degrees north. His chart is a clean illustration because his latitude pushes Placidus to an extreme.

Nothing about the sky changed between those two pictures. The Sun is at 17 degrees of Capricorn in both. What changed is where the walls sit.

Which planets actually move

This is the check worth doing on your own chart, because the answer is different for everybody. Here is Bowie's, calculated in five systems.

Three things jump out of that table, and all three are useful.

Placidus and Koch are identical here. Every planet lands in the same house in both. Should those two have been worrying you, this is your answer for this chart: it makes no difference, so pick either and move on. Check your own chart before assuming the same, because at other latitudes they do separate.

Venus lands in three different houses. Ninth in Placidus, tenth in Equal, eleventh in Whole Sign. So is Bowie's Venus about belief and foreign places, about public reputation, or about friendship and the collective? For a man whose work was built on reinvention in front of an audience, that is not a trivial question, and the systems genuinely disagree.

Three planets never move. Sun, Mars and Pluto sit in the same house whatever you choose. Whatever those three describe in your chart is solid ground. You can trust it and stop worrying about it.

One clarification that saves a lot of confusion. Your Ascendant and Midheaven are fixed points in the sky and they never move when you change house system. In Whole Sign and Equal, the tenth house simply stops beginning at the Midheaven, so the MC floats somewhere inside the ninth or tenth. The point itself has not gone anywhere.

How to choose, in four steps

1. Narrow to two candidates

Do not test eleven. Test two. If you were born below about 40 degrees latitude, try Placidus and Whole Sign. If you were born above 50, try Whole Sign and Placidus as well, because that is where they disagree most and the comparison is most informative. Working already inside a tradition? Use its system as one of your two: Whole Sign for Hellenistic, Regiomontanus for horary, Koch for psychological work.

2. Read only the house sections

Run your natal report twice, once in each system, and ignore everything that does not mention a house. Your sign placements, your aspects and your elemental balance will be identical both times, so they tell you nothing about the choice. What you are comparing is the planets-in-houses commentary and the house cusp rulers. On this site, the House System button at the top of any report switches it and regenerates everything below.

3. Judge it against what already happened

This is the step that makes the decision honest. Do not ask which version sounds more appealing or more flattering. Ask which one describes the life you have already lived.

Take Bowie's Venus. A ninth house Venus says the loves and values are bound up with belief, distance and meaning. An eleventh house Venus says they are bound up with friendship, groups and the wider public. Both are plausible on paper. Only one matches the decades of evidence. Apply the same test to your own: if one version puts Saturn in the sixth and the other puts it in the seventh, you already know whether the long hard lesson of your life has been about work and health or about partnership. Let the past cast the vote.

4. Notice anything sitting on a cusp

If a planet is within two degrees of a house boundary, no system is going to settle it for you, and small corrections to your birth time will move it back and forth. Treat those planets as belonging to both houses, read both interpretations, and keep the one you recognise. This is also the strongest sign that your recorded birth time deserves a second look, because near the Ascendant the houses shift by roughly one degree every four minutes.

Orbs are the same decision, with a different dial

An orb system does not change your chart. It changes how much of your chart you are shown. A wide orb counts two planets as being in aspect when they are further apart, so more aspects qualify. A tight orb admits only the close ones.

We ran Bowie's chart through seven orb standards and counted how many aspects each one found. Same planets, same positions, same everything.

Six aspects at one end and sixty-eight at the other, on one unchanged chart. That is more than eleven times as much material, and it is the single biggest reason two astrologers can look at the same person and describe two different people.

Choosing is easier than it looks, because the question is only about how much noise you want. If you are new to your chart or you want the few loudest signals, go tight and work with Traditional Moiety or Huber. For the full texture, when you are comfortable weighing what matters, go wide. If you have no strong feeling, leave it on Practical Standard, which is where we set it precisely because it sits in the middle.

One thing to hold on to. A tight aspect is always stronger than a wide one, whatever system you use. Every aspect in our reports prints its exact orb next to it, so a conjunction at 0 degrees 20 minutes and one at 7 degrees are easy to tell apart. Widening your orbs adds quieter material to the bottom of the list and never promotes it to the top.

Node and Lilith: two small dials

These two sit together in the panel and neither is going to reshape your chart. Both exist because the Moon's orbit wobbles, and in each case you are choosing between a smoothed average and the exact instantaneous position.

Moon's Node, Mean or True

The nodes are where the Moon's path crosses the Sun's path. That crossing point drifts backwards through the zodiac, and it does so unevenly, oscillating slightly as it goes. Mean smooths the wobble into a steady average. True gives you the actual position at your moment of birth.

On Bowie's chart the mean node sits at Gemini 9°45' and the true node at Gemini 11°18'. The gap is 1.5 degrees, and the two never separate by more than about 1.8. Same sign, and in almost every chart the same house.

Leave it on Mean unless you have a reason. Most published node interpretations are written for the mean node, and it is the steadier reference when you are tracking nodal returns or eclipses. Switch to True when you want the exact degree for a tight transit, or when the node sits within about two degrees of a sign or house boundary and you need to know which side it was actually on.

Lilith, Mean or True Osculating

Black Moon Lilith is not a body at all. It is the empty focus of the Moon's elliptical orbit, the point the Moon swings furthest from. Mean Lilith moves at a steady rate. True, or osculating, Lilith tracks the real geometry, which lurches, reverses direction and can move several degrees in a few days.

This one is worth checking, because the two versions separate much further than the nodes do. Bowie's mean Lilith is at Sagittarius 27°30' and his osculating Lilith at Capricorn 2°51'. That is 5.3 degrees apart, and it lands them in different signs.

Mean is the sensible default and it is what the great majority of Lilith writing assumes. Osculating appeals to people who want the literal astronomy, and it is the more volatile reading of a point that is already about volatility. The one time the choice genuinely matters is the situation Bowie is in, where the two versions fall either side of a sign boundary and you are being told two different stories.

There is one place where the node setting stops being a small dial. A draconic chart is your natal chart rotated so the North Node sits at 0 degrees of Aries, which means the node's longitude defines the whole frame. Switch between mean and true on the Draconic Soul Blueprint or Draconic Synastry and every single position moves, along with every aspect between them. The Uranian report is similar, because the node is one of the personal points its house framework is built from. On those reports, pick one mode and keep it.

Everywhere else, neither of these settings will rescue a chart that feels wrong. When a reading is not landing, the house system and your birth time are where the problem almost always lives.

Then stop changing it

This matters more than which one you land on. Once you have run the comparison and something fits, stay with it for a year and read everything in it.

Astrology is a language you learn by repetition. A twelfth house means something specific to you only after you have watched your own twelfth house behave across transits, progressions and a few solar returns. Every time you switch systems you reset that learning and you lose the accumulated sense of what your own houses feel like in practice. People who switch whenever a reading disappoints them never build the fluency, and the fault is rarely the system.

Keep a note of what you chose and why. Write down the date. If in two years the chart consistently stops matching your life, run the comparison again with that much more evidence behind you. That is a considered revision. Changing it every month because one paragraph missed is not.

Where the settings are

On any report, the bar under your birth details shows what that report is currently using: Zodiac, House System and Orb System, each with a Change button. The full panel, including the Node and Lilith selectors, opens under Extended settings. Press one, choose, and the report rebuilds with your setting applied.

Two things about that panel are worth knowing before you go looking for a control that is not there. The panel only appears once a chart is loaded, and each setting is shown only on the reports where it would actually change something.

One limitation to plan around. These settings live in the page address, so they apply to the report you are on and are not remembered. Open a different report from the menu and it starts at its own default. If you have settled on a combination you like, the reliable way to keep it is to bookmark a report with the settings already in the address.

Different reports start from different defaults on purpose, because each tradition was built on a particular system. The natal chart opens in Placidus. Horary opens in Regiomontanus, which is what horary was designed around. The Traditional report opens in Whole Sign. You are free to override any of them, and the bar always tells you what is in force, so you are never reading a chart without knowing how its houses were drawn.

For the background on how the systems differ, our article on house systems in astrology covers the geometry with a worked example in seven systems, and our article on orb in astrology sets out each standard in detail. This one was only meant to get you to a decision.