Combustion (asta) of planets near the Sun
Combustion (asta) describes a planet that lies too close to the Sun in the sky, so that it is hidden in its glare. The classical texts treat combust planets as weakened.
What it is
Commonly cited orbs are about 12 degrees for the Moon, 17 for Mars, 14 for Mercury, 11 for Jupiter, 10 for Venus and 15 for Saturn. Some sources reduce the orb for a retrograde Mercury or Venus. The exact values vary between texts and should be checked.
How it is worked out or read
The distance from the Sun is the difference of sidereal longitudes, taken as the smaller angle. The Sun is never combust.
Where it appears on this site
This site does not yet mark combustion in its charts. The distance can be found by comparing the grahas' longitudes in the birth chart.
What combustion means
Combustion, asta in Sanskrit, describes a planet that lies so close to the Sun in the sky that it is lost in the Sun's glare and cannot be seen. In the classical view a combust planet is weakened, because its expression is said to be overpowered by the Sun. The idea is a tradition and not a physical effect on the planet, but it is a widely used rule, and the reader should know how it is applied before using it.
How close is too close
The orbs of combustion are the distances from the Sun within which a planet counts as combust. Commonly cited values are about 12 degrees for the Moon, 17 for Mars, 14 for Mercury, 11 for Jupiter, 10 for Venus and 15 for Saturn, with some sources reducing the orb for a retrograde Mercury or Venus. These values differ between texts, so a reader should state which orbs are used. The Sun is never combust.
Working out the distance
To check combustion, compute the sidereal longitudes of the Sun and of the planet in question, subtract them and take the smaller angle. Compare the result with the orb of that planet in the chosen source. The site does not yet mark combustion in its charts, so the check is done by hand from the table of longitudes in the birth chart.
Combustion in practice
Combustion matters most for grahas that the reader is considering as significators of an important theme. If a graha is combust, the reader should describe its theme as weakened in expression, and check whether the chart shows the same theme through other grahas. Combustion is one of the classical weakening rules, and it is applied with the orbs of the chosen source.
Combustion and the Sun's brightness
The classical idea is that a graha close to the Sun is overpowered by its light. A reader may describe this as a sense of the planet's expression being absorbed into the Sun's stronger identity, while noting that the traditional orbs and their use vary between sources.