Combustion (Asta): The Degrees at Which a Graha Stops Being Readable
On this page, 8 sections
Here is a pattern I see constantly. Somebody has a beautiful looking placement. Venus exalted, or Jupiter in its own sign, or Mercury sitting in the tenth house exactly where a career reading would want it. And the person reading their own chart cannot work out why the life does not match the description at all.
Very often the missing variable is combustion, called asta in Sanskrit. The graha is too close to the Sun in longitude, and the classical texts treat that as a condition that changes how the graha expresses. It is one of the least glamorous factors in the whole system and one of the most explanatory.
What asta actually describes
Asta means set, in the same sense as a star setting. The condition is about visibility. A graha within a certain angular distance of the Sun is lost in solar glare and cannot be seen from Earth at all, either before dawn or after dusk. It is physically still there, still moving through its sign, and completely invisible to the naked eye.
That physical fact is the whole basis of the doctrine. The tradition takes visibility seriously as a marker of a graha’s capacity to act on its own terms. A graha that has disappeared into the Sun’s light is treated as having surrendered its independent voice for the duration.
This matters for interpretation in a very specific way, which I will get to. First, the numbers.
The orb table
The commonly cited combustion orbs, measured as the difference in longitude between the graha and the Sun, are these:
- Moon: 12 degrees
- Mars: 17 degrees
- Mercury: 14 degrees direct, 12 degrees retrograde
- Jupiter: 11 degrees
- Venus: 10 degrees direct, 8 degrees retrograde
- Saturn: 15 degrees
Different digests give slightly different values, and a few traditions add a narrower inner band for extreme proximity. This is the set most widely used and the one derived from the heliacal visibility arcs in the siddhānta literature. [NEED: confirm which orb table this site’s engine applies before quoting these as the engine’s own values]
The rarely said reason the orbs differ
Almost nobody explains why these six numbers are different from each other, and once you see it the table stops being something to memorise.
Sort the orbs from smallest to largest. Venus 10, Jupiter 11, Moon 12, Mercury 14, Saturn 15, Mars 17. Now sort the same bodies by how bright they appear in the sky.
Venus is the brightest object in the sky after the Sun and Moon. Jupiter is next. The Moon near conjunction is a very thin crescent. Mars near the Sun is at its most distant point from Earth and correspondingly faint.
The two orderings match. The brighter the object, the smaller its combustion orb, because a bright object can be seen closer to the Sun’s glare. The table is not an arbitrary list handed down. It is a record of the angular distance at which each body actually reappears from the twilight, which observers measured and wrote down.
That also tells you what the doctrine is really tracking. It is tracking observability, and the interpretive claim is built on top of the observation.
Why retrograde Mercury and Venus get a tighter orb
Mercury and Venus are the two grahas that can pass between Earth and the Sun. When either is retrograde and near the Sun, it is at inferior conjunction, the near side of its orbit, where its apparent motion relative to the Sun is fastest and it clears the glare at a smaller elongation than it would on the far side.
So the digests reduce the orb: Mercury from 14 to 12, Venus from 10 to 8. The rule is consistent with the visibility logic underneath the whole doctrine, which is a decent sign it belongs there rather than being a later invention.
The arithmetic that should stop you worrying
Now the point that defuses most of the anxiety around this topic.
Mercury never appears more than about 28 degrees away from the Sun as seen from Earth. That is a hard limit set by the size of its orbit. The combustion orb for Mercury is 14 degrees. So half of Mercury’s entire possible range of separation from the Sun falls inside the combustion band.
Combust Mercury is therefore an extremely ordinary condition, present in a very large share of all charts ever cast. It cannot mean a broken mind or a damaged intellect, because that description would apply to a substantial fraction of humanity. Anyone who tells you a combust Mercury is a serious problem has not done this piece of arithmetic.
Venus reaches about 47 degrees of elongation and has a 10 degree orb, so combust Venus is meaningfully rarer than combust Mercury while still being common. The outer grahas can be anywhere from 0 to 180 degrees from the Sun, so combustion for Mars, Jupiter and Saturn is genuinely uncommon.
The misreading worth correcting
The standard popular claim is that a combust graha is burnt, destroyed, or gives no results. That is a translation of asta that the word does not carry, and it produces readings that are both wrong and needlessly frightening.
What the classical position describes is a loss of independent expression. The graha keeps its significations. What changes is that those significations now run through the Sun’s agenda, which is identity, authority, visibility, the father, and the person’s sense of who they are.
A combust Venus does not remove the capacity for beauty and relationship. It tends to fuse that capacity to the person’s identity, so that their aesthetic and their relationships become statements about who they are.
You can see the same fusion described from the other direction in the Sun in the first house, where identity itself takes the front position. And a combust Mercury tends to produce someone whose thinking is inseparable from their sense of self, which is a recognisable pattern rather than a defect. Mercury in the first house covers the shape of that.
The technical detail everyone misses
Combustion is measured by difference in longitude, and it pays no attention to sign boundaries.
A graha at 28 degrees of Aries and a Sun at 2 degrees of Taurus are 4 degrees apart. The graha is deeply combust. They are in different signs, they are not conjunct in the ordinary chart-reading sense, and most people looking at that chart will never notice, because the two bodies appear in different boxes.
The reverse also happens. A Sun at 1 degree of Leo and a Venus at 25 degrees of Leo sit in the same sign and look conjunct on the chart, and at 24 degrees of separation Venus is nowhere near combust. Same sign proves nothing either way. Only the degrees decide.
This single point resolves a large fraction of the disagreements I see about whether a given chart has a combust graha.
What is never combust
The Sun cannot be combust, since combustion is measured from the Sun and its separation from itself is always zero degrees by definition. This is worth saying out loud because the Sun attracts a lot of confused claims, including the persistent one that it can go retrograde, which I took apart in the Sun retrograde myth.
Rāhu and Ketu are also never combust. They are computed points, the intersections of the Moon’s orbital plane with the ecliptic, and they have no physical body to disappear into the Sun’s glare. Any software that reports a combust Rāhu is applying a rule outside its domain.
How to check it, and what to do with the answer
Take the Sun’s longitude and the graha’s longitude in absolute degrees from 0 Aries. Subtract. If the result is more than 180, subtract it from 360. Compare that to the orb for that graha, remembering to use the retrograde value if Mercury or Venus is retrograde. That is the entire calculation.
If you find a combust graha, the useful response is to read it as fused to identity rather than to read it as damaged. Ask what that graha’s significations look like when they cannot be separated from the person’s sense of self.
For a combust Venus, look at whether relationships and taste have become identity statements, which is the same territory Venus in the first house describes.
There is nothing here to fix and nothing to buy. Combustion is a description of a geometry that was true at a moment. Reading it accurately is the entire point.
What is combustion or asta in Vedic astrology?
A graha is combust when it lies within a specific number of degrees of the Sun in longitude, close enough that it is lost in solar glare and invisible from Earth. The Sanskrit term asta means set, in the sense of a star setting, and the doctrine is built on that observable fact of visibility.
What are the combustion degrees for each planet?
The commonly cited orbs are Moon 12, Mars 17, Mercury 14 (12 when retrograde), Jupiter 11, Venus 10 (8 when retrograde) and Saturn 15 degrees. Digests differ slightly. The ordering follows how bright each body appears, since a brighter object can be seen closer to the Sun.
Does combustion destroy a planet’s results?
No. What the classical position describes is a loss of independent expression, with the graha’s significations running through the Sun’s agenda of identity and authority instead of standing on their own. The significations remain. Their route into the life changes.
Why is combust Mercury so common?
Because Mercury never appears more than about 28 degrees from the Sun, and the combustion orb is 14 degrees, so half of Mercury’s entire possible range of separation falls inside the band. A condition that common cannot reasonably be read as a defect.
Can a planet be combust while in a different sign from the Sun?
Yes, and this is the detail most readings miss. Combustion is measured purely by difference in longitude and ignores sign boundaries, so a graha at 28 degrees of Aries is 4 degrees from a Sun at 2 degrees of Taurus and is deeply combust despite sitting in a different box on the chart.
Can Rāhu and Ketu be combust?
No. They are computed intersection points of the Moon’s orbital plane with the ecliptic and have no physical body that can vanish into solar glare. The Sun likewise cannot be combust, since its separation from itself is zero by definition.