What this aspect is
Zero degrees between planets. This is not an aspect in the usual sense but a merger: two functions share one degree of the zodiac and from then on appear together. It carries the widest orb of all aspects, up to 12 degrees when the Sun is involved and 5 degrees between the other bodies.
In the natal chart
In a chart a conjunction reads as one compound function, not as two planets side by side. Sun with Mercury gives a person whose thinking is inseparable from who they are; Mars with Saturn gives action that always carries a brake. The sign and the house matter more here than with other aspects: both planets receive the same context.
In transits
A transiting conjunction starts a cycle. The moment a transiting planet reaches a natal one sets the theme for the whole following revolution: 29 years for Saturn, 12 for Jupiter. A retrograde planet crosses the degree three times, so the conjunction stretches over months and keeps returning to the same theme.
Common reading mistakes
The most common mistake is counting any two planets in the same sign as a conjunction. A conjunction is about degrees, not signs: the Sun at 2 degrees of Leo and Saturn at 27 degrees of Leo share a sign, but 25 degrees apart there is no aspect. The second mistake is stacking two separate planet descriptions instead of reading them as one function.
Major aspects
Orb by body
- Sun 12°
- Moon 10°
- Mercury 5°
- Venus 5°
- Mars 5°
- Jupiter 8°
- Saturn 5°
- Uranus 5°
- Neptune 5°
- Pluto 5°
The orb of a pair is the smaller of the two numbers. A Sun conjunct Pluto counts up to 5 degrees, because that is Pluto's figure, even though the Sun's is 12.