← Encyclopedia of Astrology · lesson 123/235
Combust
What it means
A planet is combust — literally "burnt" — when it stands so close to the Sun that it is swallowed by its light. Lilly set the limit at 8°30' either side of the Sun: a planet is combust "when he is not distant from the Sun eight degrees and thirty minutes, either before or after the Sun". That is the threshold used for combustion on this site. Closer still, within 17 arcminutes, the planet is no longer burnt but cazimi, "in the heart of the Sun". Further out, up to about 17°, it is under the beams.
So the Sun's neighbourhood has three zones:
| Distance from the Sun | Condition | Lilly's score |
|---|---|---|
| within 0°17' | cazimi | +5 |
| 0°17' to 8°30' | combust | −5 |
| 8°30' to 17° | under the beams | −4 |
| beyond 17° | free of the Sun's beams | +5 |
Why it happens
Every planet passes close to the Sun at a conjunction. For Mars, Jupiter and Saturn this is the time they disappear from the night sky for weeks before reappearing at dawn. Mercury and Venus, which never stray far from the Sun, are combust much more often — Mercury several times a year. The Moon is combust for a day or two around each new Moon, which is why she is invisible then.
How it is read
In the tradition combustion was among the gravest afflictions. Guido Bonatti called a bodily conjunction with the Sun "the greatest misfortune that can befall a planet", and Lilly scored it −5, as severe as a planet in its detriment. He added that a planet is more afflicted when the Sun is applying to it than when the Sun is moving away, "in regard it's the body of the Sun that doth afflict". In a horary question a combust significator showed the person "in great fear, and over-powered by some great person". Lilly also noted his own proviso that the planet should be in the same sign as the Sun, and invited readers to use the rule they found truest.
In modern natal practice the reading is softer. A combust planet is often described as merged with the self: its qualities are so bound up with a person's identity that they can be hard to see objectively, or are expressed through the Sun's purposes rather than on their own terms. Someone born with Mercury combust may think so closely in line with their own will that it takes others to show them their blind spots. Many astrologers add that what is hidden can also be protected, and that such planets often show their strength later in life.
In transit, a planet entering combustion is read as going quiet, and its re-emergence from the Sun's beams as a fresh start in its area of life.