Quick answer: An orb is how far from exact an aspect can be and still count. Most astrologers allow about 8 degrees for a conjunction or opposition, 7 for a square or trine, 4 to 6 for a sextile, and 1 to 3 for minor aspects. The Sun and Moon get a degree or two more. The closer the aspect is to exact, the stronger it is. Past the orb, it fades out rather than switching off.
Planets almost never sit at exact angles. A square is 90 degrees. Your Mars and Saturn might be 86 degrees apart, or 94. Is that a square or not? The orb is the rule that answers this question. Every astrologer needs one, and there is no single agreed number, which is why the same chart can show slightly different aspects on different websites.
What is an orb?
Picture the exact aspect as a bullseye. The orb is the size of the target around it. If two planets fall inside the target, the aspect counts. If they fall outside, it does not.
A square with an orb of 7 degrees counts anywhere from 83 to 97 degrees apart. A conjunction with an orb of 8 degrees counts anywhere from 0 to 8 degrees apart. The word comes from the Latin orbis, a circle, because the old texts imagined each planet surrounded by a circle of light. When two circles touched, the planets were in aspect.
What orbs do most astrologers use?
There is no law, but there is a strong habit. These are the numbers you will find in most modern books and software.
- Conjunction (0°) and opposition (180°): 8 degrees, sometimes 10.
- Trine (120°) and square (90°): 7 to 8 degrees.
- Sextile (60°): 4 to 6 degrees.
- Minor aspects such as the semi-sextile (30°), the quincunx (150°) and the quintile (72°): 1 to 3 degrees.
Our guide to aspects explained covers what each of these angles means. The point here is only how much room each one gets.
Why do the Sun and Moon get a bigger orb?
Because they are the brightest and, in the tradition, the most important bodies in the chart. Most astrologers add one or two degrees when the Sun or Moon is one of the two planets. A Sun-Saturn square at 9 degrees still counts. A Mercury-Saturn square at 9 degrees is borderline.
The other thing that earns a wider orb is the aspect itself. A conjunction is the strongest aspect, so it gets the widest orb. A sextile is the gentlest, so it gets a narrow one. Minor aspects are subtle, and a wide orb would flood the chart with noise, so they are held to two or three degrees.
How did classical astrologers do it?
Differently, and the difference is worth knowing. The old method did not give an orb to the aspect. It gave an orb to the planet. William Lilly's table, still widely quoted, runs roughly like this.
- Sun: 15 degrees
- Moon: 12 degrees
- Jupiter and Saturn: 9 degrees
- Mars: 7 degrees
- Venus and Mercury: 7 degrees
To test an aspect you take half of each planet's orb, called its moiety, and add the two halves together. The Sun's moiety is 7.5 and Saturn's is 4.5, so a Sun-Saturn aspect counts up to 12 degrees from exact. A Mercury-Venus aspect counts up to 7. This method gives every pair its own allowance, and it is why classical charts show wider aspects involving the lights and tighter ones between small planets.
Neither method is wrong. The modern method is simpler. The classical method is more careful about which planets are involved. Many working astrologers use the modern numbers and keep the classical logic in the back of their mind.
Does a tight aspect matter more than a wide one?
Yes, and this is the most useful rule in the whole subject. An aspect at 1 degree from exact is loud. The same aspect at 7 degrees is a murmur. When you read a chart, start with the aspects inside 3 degrees. Those are the ones that describe the person clearly. The wide ones add colour, but they do not carry the chart.
Whether the aspect is applying or separating matters too. An applying aspect, where the faster planet is still moving toward exact, is read as stronger and more forward-looking than one that has already passed. Our article on applying and separating aspects explains this.
What happens just outside the orb?
Nothing dramatic. An aspect does not switch off at 8 degrees and 1 minute. It fades. Two planets 9 degrees apart in a square are not in a square by the usual rule, but they are not strangers either. If a transit or progression later closes the gap, the aspect comes alive for a while.
So treat the orb as a working boundary, not a wall. If a chart feels like it has a certain aspect and the planets are one degree past the usual orb, most astrologers would let it in and note that it is weak.
Frequently Asked Questions
What is an orb in astrology?
An orb is the number of degrees an aspect can be from exact and still count. A square is 90 degrees, and with a 7-degree orb any distance from 83 to 97 degrees is read as a square.
What are the standard orbs for aspects?
About 8 degrees for conjunctions and oppositions, 7 for squares and trines, 4 to 6 for sextiles and 1 to 3 for minor aspects. The Sun and Moon usually get one or two degrees more.
Why do different websites show different aspects for my chart?
Because they use different orbs. A site with an 8-degree orb for squares shows an 8-degree square. A site with a 6-degree orb leaves it out. Your free birth chart lists the exact distance for each aspect so you can judge for yourself.
Is a 10-degree conjunction still a conjunction?
By most modern rules it is at the edge, and only if the Sun or Moon is involved. By the classical moiety method a Sun-Jupiter conjunction counts up to 12 degrees, while a Mercury-Mars conjunction stops at 7. Either way, at 10 degrees the aspect is weak and should be read lightly.
This is classical guidance built on a real chart. It is not scientific proof, and it is not a prediction of fixed events.