What Is an Orb in Astrology?

An orb is the amount of distance allowed between two planets and the exact angle of an astrological aspect.

Aspects are based on specific angles. A conjunction is 0°, a sextile is 60°, a square is 90°, a trine is 120° and an opposition is 180°.

The planets do not have to sit on the exact degree for the aspect to count. The orb tells you how far away from exact they can be.

How Does an Orb Work?

Suppose the Sun is at 10° Aries and Mars is at 10° Cancer.

That is an exact square because Aries and Cancer are 90 degrees apart.

Now suppose Mars is at 13° Cancer instead.

The square is no longer exact. It is three degrees away from exact, so the aspect has a 3° orb.

Astrologers then decide whether that distance is still close enough for the square to be used.

What Does a Tight Orb Mean?

A tight orb means the planets are very close to the exact angle.

If two planets are only one degree away from an exact aspect, that aspect is usually considered strong.

A wider orb means the planets are further from exact.

In simple terms, the closer the aspect, the stronger it is usually considered to be.

This is why exact degrees matter so much when reading a birth chart.

Do All Aspects Use the Same Orb?

No.

Astrologers often allow wider orbs for major aspects such as conjunctions and oppositions. Smaller orbs are usually used for less important aspects.

The Sun and Moon are also often given wider orbs because they are such important points in a birth chart.

There is no single orb rule used by every astrologer.

One astrologer might allow an 8° orb for a conjunction, while another might prefer 6°. Some will use very tight orbs when looking at transits.

The important thing is to use a clear system and stay consistent.

Why Does the Orb Matter?

The orb tells you how close two planets are to forming an exact relationship.

Take Venus and Saturn.

If Venus is at 15° Taurus and Saturn is at 15° Aquarius, the square is exact.

If Saturn is at 17° Aquarius, the square has a 2° orb.

If Saturn is at 22° Aquarius, the square has a 7° orb.

All three can still be treated as squares depending on the orb being used, but the first one is exact and the others are increasingly wider.

The orb helps show how strongly the aspect is working.

Applying and Separating Aspects

Astrologers can also look at whether an aspect is applying or separating.

An applying aspect means the planets are moving closer to the exact angle.

A separating aspect means they have already formed the exact aspect and are moving apart.

For example, if Mars is moving towards an exact square with Saturn, the aspect is applying. Once Mars passes the exact degree and moves away, it becomes separating.

This adds another layer to the interpretation.

Orbs in a Birth Chart

In a birth chart, orbs help determine which planetary aspects are important enough to include.

Without orbs, astrologers would only count perfectly exact aspects, which would leave out many meaningful planetary connections.

A person can have Mercury at 5° Gemini and Jupiter at 8° Libra. The planets are not exactly 120 degrees apart, but they are close enough to form a trine under many orb systems.

The orb tells you the difference between the exact angle and the actual positions.

Orbs in Transits

Orbs are also important when reading transits.

A transiting planet can begin affecting a natal planet before the aspect becomes exact. It then reaches the exact degree and later moves away.

With a slow-moving planet such as Saturn, Uranus, Neptune or Pluto, this process can last a long time.

Retrograde motion can also cause the same aspect to become exact more than once.

For transit work, astrologers often use tighter orbs than they would in a birth chart because the exact timing matters more.

Does a Wider Orb Mean the Aspect Does Not Matter?

Not necessarily.

A wider aspect can still be important, especially if it involves the Sun, Moon or an important point in the chart.

But as the orb grows wider, the connection becomes less exact.

This is why astrologers do not normally treat a 1° square and an 8° square as though they are identical.

Both can matter, but the tighter aspect will usually stand out more strongly.

How Do You Calculate an Orb?

First work out the exact angle of the aspect.

Then compare that angle with the real distance between the planets.

If two planets are 92 degrees apart, they are two degrees away from an exact 90° square.

The orb is therefore 2°.

If two planets are 118 degrees apart, they are two degrees away from an exact 120° trine.

Again, the orb is 2°.

Once you understand planetary degrees, calculating a basic orb is straightforward.

What an Orb Means in Astrology

An orb is the distance between an exact astrological aspect and the actual positions of the planets.

It tells astrologers whether two planets are close enough to be considered in aspect and how exact that connection is.

A tight orb usually gives the aspect more weight. A wider orb can still matter, but the connection is less exact.

The aspect tells you the type of relationship between the planets. The orb tells you how close that relationship is to exact.