A graha is asta, or combust, when it sits within a set number of degrees from the Sun: 12° for the Moon, 17° for Mars, 14° for Mercury (12° when retrograde), 11° for Jupiter, 10° for Venus (8° when retrograde) and 15° for Saturn. A combust graha gives less of its own results.
The idea in plain words
Seen from Earth, a graha near the Sun disappears in its glare. Jyotish reads that as the graha losing its voice: its matters are pushed aside by the Sun's, which are the self, authority and the father. A combust Mercury, for example, can still give a sharp mind, but the person may struggle to be heard, or may speak in a way shaped by pride.
Step 1: the degree limits
| Graha | Combust within (direct) | Combust within (retrograde) |
|---|---|---|
| Moon (Chandra) | 12° | the Moon is never retrograde |
| Mars (Mangal) | 17° | 17° |
| Mercury (Budh) | 14° | 12° |
| Jupiter (Guru) | 11° | 11° |
| Venus (Shukra) | 10° | 8° |
| Saturn (Shani) | 15° | 15° |
These are the classical values, the same ones the free kundali uses to mark a graha with a small C. Rahu and Ketu are never combust, since they are points, not bodies. The Sun itself cannot be combust.
Step 2: measure the distance in degrees, not signs
Combustion counts degrees across sign borders. The Sun at 28° Mesh and Mercury at 3° Vrishabh are 5° apart, so Mercury is combust even though it sits in the next sign. The Sun at 2° Mesh and Mercury at 27° Mesh are 25° apart, so Mercury is not combust even though they share a sign.
Step 3: read what the graha loses
Each graha loses its own matters. A combust Moon, which is the Moon close to the new Moon, gives a quieter, more private mind. A combust Mars dulls drive and courage, or turns them toward the father's goals. A combust Mercury gives quick thought with nervous strain. A combust Jupiter makes teachers and advice harder to find. A combust Venus can put duty ahead of love. A combust Saturn brings friction with authority over work.
Step 4: weigh the exceptions
Combustion is one factor among many. A combust graha in its own sign or exalted still gives a good deal. A retrograde graha, such as Mercury, has a smaller limit and some astrologers treat it more leniently. Some texts also hold that Mercury, which is combust so often, suffers less from it than the others. Classical texts do not agree on every case, so read combustion alongside dignity, house and aspects.
A worked example
Take a chart with the Sun at 20° Simha, Jupiter at 12° Simha, Venus at 26° Simha and Mercury at 8° Kanya. Jupiter is 8° from the Sun, inside its limit of 11°, so it is combust. Venus is 6° away, inside its limit of 10°, so it is combust too. Mercury is 18° away, outside its limit of 14°, so it is free even though the Sun is close.
The reading follows. Jupiter, the graha of teachers, children and wisdom, is overshadowed by the Sun's pride in its own sign, so advice may be hard to take and recognition for learning comes late. Venus, the graha of love and comfort, takes second place to status and duty. Mercury keeps its own voice and is the clearest graha of the three in this chart. If any of them were retrograde, the check would use the smaller retrograde limit.
Combustion in transit
Each year every outer graha spends a few weeks combust around its meeting with the Sun, and Mercury and Venus do so several times. In transit, a combust graha's own matters slow down for those weeks, while the Sun's matters, such as authority and recognition, take over. The Grah Gochar 2027 table shows where each graha is through the year.
Where people go wrong
The first mistake is counting by sign: same sign does not mean combust. The second is treating every combust graha as ruined, when it still gives results, only fewer of its own. The third is forgetting the retrograde limits for Mercury and Venus. The fourth is mixing combustion with the Moon's darkness at Amavasya, which is related but read on its own as the Moon's phase.
Check your own
Open your free kundali and look for a small C next to any graha. Then find its distance from the Sun in degrees. A graha near the edge of its limit, say Mercury at 13°, is only slightly affected. A graha within a few degrees of the Sun is the strongest case. The yuti guide shows how combustion fits into reading a conjunction with the Sun.