Moolatrikona
Moolatrikona is a planet’s “office”: a set range of degrees in one sign where it works with special authority, ranking just below exaltation. Six of the seven planets have it in one of their own signs.
Also known as: mooltrikona, mool trikona, mulatrikona, root trine
Mula means root. Parashara assigns each planet a moolatrikona range: Sun, Leo 0–20°; Moon, Taurus 3–30°; Mars, Aries 0–12°; Mercury, Virgo 15–20°; Jupiter, Sagittarius 0–10°; Venus, Libra 0–15°; and Saturn, Aquarius 0–20°. Elsewhere in the sign the planet counts as being in its own sign, or for the Moon and Mercury, partly in exaltation.
Astrologers rank dignity as a ladder: exaltation, then moolatrikona, then own sign, then friendly, neutral and enemy signs, and finally debilitation. A planet in moolatrikona is comfortable and purposeful, like an official at their own desk, and tends to give steady results for the houses it rules.
Moolatrikona also guides technical judgements, such as which of a planet’s two signs acts as its main seat, and it feeds into strength calculations. Texts differ on Rahu and Ketu, so many astrologers do not assign them one.