Astrology aspects and orbs: the setting nobody tells you
An orb decides how far from an exact angle two planets can be and still count. It is chosen by the astrologer, rarely stated, and it determines how much of your chart exists. Move the slider and watch aspects appear from nothing.
An aspect is two planets at a meaningful angle — 90°, 120°, 180°. An orb is how far off that angle they are still allowed to be and count.
The orb is where the trouble is. It is chosen by the astrologer, it is rarely stated, and it decides how much of your chart exists.
Drag it and watch
Seven fixed positions, unchanged as you move the slider. At a 3° orb the chart is nearly quiet. At 10° it is crowded with significant angles. Nothing moved. The only thing that changed is a threshold somebody picked.
Now consider that no widely agreed standard fixes that number. Common practice runs from about 3° to 10° depending on the aspect, the bodies involved, the school, and — this is the part worth naming — how much the reading needs to say.
A parameter set after seeing the chart is not a measurement.If an aspect can be admitted by widening the orb and dismissed by narrowing it, then its presence in your reading is a decision rather than a finding — and you were not told a decision was made.
Why the Vedic treatment is structurally tighter
Vedic aspects mostly work by whole sign. Every planet aspects the sign opposite it; Mars, Jupiter and Saturn have additional fixed aspects to particular signs from their own. A planet either aspects a sign or it does not.
That is cruder. It also cannot be tuned. There is no dial to turn after seeing what the chart needs to say, which removes a degree of freedom rather than hiding one.
- Degree-based with orbs — finer, and adjustable by whoever is reading
- Whole-sign — blunter, and fixed before anybody looks
Neither is demonstrated to be more accurate. But only one of them can be quietly widened until the reading works, and that asymmetry is worth knowing about when you are deciding how much weight to give an aspect somebody has told you about.
The general principle, which outlasts this page
Every free parameter in a system is a place where the answer can be fitted to what is already known. Orbs are the clearest example because you can watch them work, but the same test applies elsewhere: which divisional chart, which dasha system, which ayanamsa, which house system.
The question to ask is not “is this technique valid”. It is“was this setting chosen before or after looking at my chart, and can you tell me what it was?” A reading that cannot answer that is not necessarily wrong, but it is unfalsifiable, and unfalsifiable is a much weaker thing than true.
What we do about it
Every setting is fixed in advance and published onthe calculation rules page — before any particular chart exists, so none of them can be tuned to make a reading come out better.
Our chart files state the basis under each finding, so an aspect appears with the positions and the rule that produced it rather than as an assertion you have to take on trust.
Related: seven things to check before buying a reading, andten ways a false claim becomes tradition.