Enter your birth date, time and place above and this free calculator shows which planets were combust, or asta, at your birth. For each of the Moon, Mars, Mercury, Jupiter, Venus and Saturn you see its distance from the Sun, its orb, whether it was inside the orb and by how much, and for a combust planet the dates and times it entered and left the orb.
How it works
The calculator works out the sidereal position of the Sun and of each planet at your birth (Lahiri ayanamsa, from the NASA JPL DE440 tables) and measures the distance of each planet from the Sun along the zodiac. A planet closer to the Sun than its orb is combust. The orbs, in degrees, are those of the Surya Siddhanta (ch. 9, verses 6 to 9, and ch. 10, verse 1, in Ebenezer Burgess’s translation of 1860):
| Planet | Orb |
|---|---|
| Moon | 12 |
| Mars | 17 |
| Mercury | 14, or 12 when retrograde |
| Jupiter | 11 |
| Venus | 10, or 8 when retrograde |
| Saturn | 15 |
For a combust planet the calculator then steps backwards and forwards in time to find when the planet entered the orb and when it left it, using the same test at every moment. These are the same positions and orbs the free kundali and the yoga finders use, so all of them agree on which planets are combust.
Reading the result
The answer at the top names the combust planets, if any. The table gives each planet’s sign and degree, its distance from the Sun, its orb, and how far inside or outside the orb it stood. “Inside the orb” is the plain measure of how deep the combustion was: a planet a few minutes inside its orb was only just combust, while one many degrees inside was close to the Sun. A combust Moon is a Moon within 12 degrees of the Sun, which happens around every new moon (Amavasya).
Many teachers read a combust planet as one whose results are dimmed or come with effort, and weigh it with the planet’s sign, house and dasha. The Sun itself is never combust, and Rahu and Ketu, which are points rather than bodies, are not counted.
Where traditions differ
The orbs differ a little between texts and teachers, and this page follows the Surya Siddhanta. In that text the smaller orb of Venus applies to her setting in the west and rising in the east, which happen around her retrograde turn, and the smaller orb of Mercury to his retrograde motion; our engine uses the smaller orb whenever the planet is retrograde. The text measures the orbs in degrees of time, and in its words a planet closer than this becomes invisible, its form “swallowed up by the brightness of the sun”. Degrees of time are the arc of the equator that rises or sets at the place between the planet and the Sun (ch. 9, verses 4 and 5), so they depend on the signs, the latitude of the place and the planet’s own latitude. Our engine, like most Jyotish software, applies the same numbers to the distance in longitude. The two measures often differ by more than a degree and sometimes by several, more so far from the equator, so a calculation done the textual way can name different planets as combust: in our checks over 2020 to 2025, for planets within 20 degrees of the Sun, the two gave a different answer in about 9 percent of cases at Mumbai and 23 percent at London.
Teachers also differ on how to weigh combustion: whether a retrograde or exalted planet is less affected, and whether the Moon should be counted at all. The calculator reports the measurement and leaves that weighing to the reading.
What it does not do
It does not grade combustion into good and bad or predict its effects, and it offers no remedy. Combustion is common, especially for Mercury and Venus, which never stray far from the Sun. It is one condition among many, and nothing here is a reason for worry. To see which planets were retrograde at your birth, use the retrograde planets calculator; for two planets very close to each other, see Graha yuddha.
Frequently asked questions
↳ What does combust mean in astrology?
A combust (asta) planet stands so close to the Sun that it is lost in the Sun's light. The Surya Siddhanta gives an orb for each planet; inside it, in the text's words, the planet becomes invisible, its form "swallowed up by the brightness of the sun".
↳ What are the combustion orbs?
This page uses the Surya Siddhanta's: the Moon 12 degrees, Mars 17, Mercury 14 (12 when retrograde), Jupiter 11, Venus 10 (8 when retrograde) and Saturn 15. Other texts and teachers use slightly different numbers.
↳ How do I know how deep the combustion is?
The table shows how far inside its orb each combust planet stood. A planet just inside the orb was barely combust; one far inside was close to the Sun. The calculator also gives when the combustion began and ended.
↳ Why is Mercury so often combust?
Mercury never strays far from the Sun as seen from the Earth, so it is often inside its orb. Venus also stays near the Sun, though with a wider swing. That is why combustion of these two is common and is read with care rather than alarm.
↳ Is the Moon combust at every new moon?
By the orb used here, the Moon is combust whenever it is within 12 degrees of the Sun, which happens around every new moon (Amavasya). Some teachers do not count the Moon's combustion in a birth chart; the table shows it so you can decide.
↳ Why does another website show a different combust planet?
Usually because it uses different orbs, a different ayanamsa, or measures the distance another way. Measured in degrees of time, as the Surya Siddhanta does, the distance from the Sun often differs from the distance in longitude by more than a degree and sometimes by several, so a planet a few degrees inside or outside its orb here can go the other way. This page names its orbs and its method.