Combust Planets and Cazimi: When a Planet Gets Too Close to the Sun

Before astrology had mathematics, it had eyes. Babylonian sky-watchers logged the evenings a planet sank into the sunset glare and the mornings it climbed back out of the dawn, and they treated the missing weeks in between as meaningful: the planet had walked into the king’s house and could not be seen. That observation survives in your birth chart under two of astrology’s best words — combust, for a planet drowned in the Sun’s light, and cazimi, for the rare hours it sits in the Sun’s exact heart.

What “combust” actually means

Combustion is a simple measurement dressed in dramatic clothing: a planet is combust when its zodiac longitude is within a few degrees of the Sun’s. Nothing is burning. The planet is simply lost in glare — too close to the Sun, from Earth’s point of view, to be visible before dawn or after dusk. The old astronomy and the old astrology are the same fact here: a combust planet is one you cannot see.

Tradition reads that invisibility as a working metaphor. A combust planet’s agenda is absorbed into the Sun’s — into identity, ego, the main plot of the personality. Combust Mercury thinks in the first person and hears feedback as a review of the self, not the idea. Combust Venus loves privately, or on the Sun’s terms. The planet still works — often intensely — but it struggles to be seen as itself, by others and by its owner. Read it as a tendency with a volume knob, not a verdict: the glare is a place a planet stands, not a sentence passed on it.

Just outside combustion sits a milder zone the medievals called under the beams — roughly within 15–17° of the Sun, dimmed but not erased. You’ll meet the phrase in older books and modern Twitter threads alike.

How close is too close? The classical orbs

Traditions disagree on the numbers, honestly and permanently. Medieval Western astrology used one blanket figure: combust within about 8°30′, under the beams to about 17°. Jyotish (which calls a combust planet asta, “set”) gives each planet its own orb, and those are the values used for every date in this article:

Planet	Combust (asta) within	While retrograde
Moon	12°	—
Mars	17°	—
Mercury	14°	12°
Jupiter	11°	—
Venus	10°	8°
Saturn	15°	—

One quietly beautiful property: combustion is a separation between planet and Sun, so it reads identically in tropical and sidereal zodiacs — the ayanamsa that moves your sign between the two systems subtracts from both longitudes and cancels out. Asta dates are one of the few things Western and Vedic calculation agree on to the minute.

The honest number: combustion is common

Here is the statistic the doom-flavoured articles skip. Run the last decade through this site’s own ephemeris — the same VSOP87 engine that draws your chart — and Mercury is combust 41% of the time. Four charts in ten. Venus, about 14%. Mercury can never stand more than 28° from the Sun, so it spends nearly half its life inside a 14° orb by construction; a combust natal Mercury is not a curse, it is the single most ordinary “affliction” in astrology. If it doomed people, doom would be the baseline. What it does mark, in the charts where it shows up, is a mind unusually fused to identity — which can read as conviction or as thin skin, depending on the decade.

Cazimi: the heart of the Sun

At the exact centre of the glare, tradition flips the verdict. A planet within about 17 arc-minutes of the Sun’s longitude is cazimi — from the Arabic kaṣmīmī, “as if in the heart” — and medieval astrologers rated it not weakest but strongest: the courtier no longer shouting from the crowd but seated beside the throne. Modern practice keeps the reversal as a metaphor for moments of unusual clarity at the midpoint of a conjunction.

The geometry gives cazimi two distinct flavours. An inferior conjunction happens when Mercury or Venus passes between Earth and Sun — always mid-retrograde, so each cazimi of this kind is the exact halfway mark of a retrograde (the date that splits the storm in half). A superior conjunction happens on the far side of the Sun, with the planet moving direct and fast — those cazimi windows run longer. Mercury’s cazimi lasts about six hours at an inferior pass and up to a full day at a superior one; slow-closing Venus can hold cazimi for two days and more.

Mercury’s combustion calendar, 2026–2027

Every window below was computed with this site’s ephemeris, using the orbs in the table above (times UT; windows given to the day).

Combust window	Cazimi (exact conjunction)	Kind
Dec 27 2025 – Feb 9 2026	Jan 21 2026 · 1°37′ Aquarius	Superior
Feb 28 – Mar 13 2026	Mar 7 · 16°53′ Pisces	Inferior (mid-retrograde)
May 1 – May 26 2026	May 14 · 23°48′ Taurus	Superior
Jul 5 – Jul 21 2026	Jul 13 · 20°42′ Cancer	Inferior (mid-retrograde)
Aug 13 – Sep 13 2026	Aug 27 · 4°27′ Virgo	Superior
Oct 30 – Nov 10 2026	Nov 4 · 12°11′ Scorpio	Inferior (mid-retrograde)
Dec 6 2026 – Jan 23 2027	Jan 1 2027 · 11°03′ Capricorn	Superior
Feb 12 – Feb 24 2027	Feb 18 · 29°48′ Aquarius	Inferior (mid-retrograde)
Apr 15 – May 11 2027	Apr 28 · 8°22′ Taurus	Superior
Jun 15 – Jul 1 2027	Jun 23 · 1°40′ Cancer	Inferior (mid-retrograde)
Jul 29 – Aug 26 2027	Aug 11 · 18°35′ Leo	Superior
Oct 13 – Oct 25 2027	Oct 19 · 26°01′ Libra	Inferior (mid-retrograde)
Nov 16 2027 – Jan 5 2028	Dec 11 · 19°38′ Sagittarius	Superior

Two dates worth circling. January 1, 2027: Mercury spends New Year’s Day cazimi in Capricorn — a twenty-three-hour window, the year’s longest. And August 11, 2027: Mercury reaches cazimi at 18°35′ Leo just as Venus closes on her own superior conjunction one degree away — a double cazimi in Leo, nine days after the total solar eclipse at 9°55′ Leo crosses Spain and North Africa. Mid-August 2027 is about as crowded as the Sun’s throne room gets.

Venus asta: the wedding-calendar planet

Venus goes combust rarely but at length, and in India the dates are civic information: tradition pauses wedding muhurta while Shukra is asta — the marriage planet is deemed unavailable while invisible. These are the current windows:

Combust window	Cazimi (exact conjunction)	Kind
Nov 26 2025 – Feb 17 2026 (~83 days)	Jan 6 2026 · 16°22′ Capricorn	Superior
Oct 19 – Oct 29 2026 (10 days)	Oct 24 · 0°45′ Scorpio	Inferior (mid-retrograde)
Jul 6 – Sep 17 2027 (~73 days)	Aug 12 2027 · 19°07′ Leo	Superior

The short 2026 window sits at the centre of Venus’s October–November retrograde — inferior conjunction on October 24, the retrograde’s midpoint. The long 2027 one swallows most of the summer. (Printed panchangs may shift any of these dates by a day or so; some use slightly different orbs or visibility-based rules. The astronomy underneath is the same.)

Reading it in your own chart

Cast your chart — free, in-browser, your birth data never leaves the device — and check whether anything shares the Sun’s sign at close quarters. The wheel shows each planet’s degree; if Mercury or Venus stands within the table’s orb of the Sun, you were born with it combust, along with a large share of humanity. Was it within 17′? Then you have a cazimi planet, which is genuinely uncommon — and, per seven centuries of tradition, a quiet superpower seated at the heart of your Sun.

The short version

Combust = too close to the Sun to be seen, read as a planet folded into the ego’s glare. Cazimi = dead centre, read as the opposite. Mercury is combust four charts in ten, so retire the doom; the interesting cases are the edges — the cazimi hours, the long Venus silences that reschedule weddings across a subcontinent. The sky does all of this on a public timetable, and your own chart will tell you in one glance which side of the glare you were born on.