A planet is combust when it is within close proximity to the Sun, weakening its influence due to the Sun's overwhelming power.
Definition
In astrology, a planet is considered combust when it is within approximately 8°30' of the Sun in a natal or horary chart. The intense radiance of the Sun is believed to overshadow and weaken the planet’s ability to express its full nature. For example, a combust Mercury may struggle to operate clearly in areas of communication or logic, as it is metaphorically 'burnt' by the Sun's overwhelming heat and light. However, interpretations can vary: some astrologers view combust planets as purified or concentrated in their expression due to their close proximity to the Sun. The degree of combustion's impact depends on factors such as the planet involved, its essential dignity, and whether it is moving toward or away from the Sun. Traditionally, the Moon and outer planets were less commonly treated as combust due to their roles in the system. Additionally, some modern astrologers consider cazimi, the condition of being within 17 arcminutes of the Sun, as a mitigating factor that enhances rather than diminishes the planet’s power.
In a chart
To identify combustion in a chart, check the proximity of any planet to the Sun, specifically within 8°30'. Ignore planets beyond this range or those in cazimi (within 17 arcminutes). Note the planet's essential dignity and aspects to assess its overall condition.