Planetary Transit (Gochar)

Each planet's sidereal longitude is computed for the dates in question, and a sign change is recorded at the moment the longitude crosses a thirty-degree boundary. Because this is arithmetic, the same date always produces the same ingress list.

Retrograde periods are the stretches when a planet appears to move backwards from Earth's vantage point. A planet can therefore cross the same boundary more than once, which is why a sign change occasionally appears to repeat within a few weeks.

Traditional practice counts a transit from the Moon sign rather than the Sun sign — Saturn over the twelfth, first and second signs from the Moon is what Sade Sati names, and Jupiter's position is likewise counted from the Moon. The same transit therefore reads differently for two people with different Moon signs.

Classical texts also treat a transit as a trigger rather than a cause: it is read as active mainly when the running Vimshottari Dasha belongs to the same planet or supports it. Outside those windows the tradition expects it to be far less noticeable.

The Moon's two-and-a-half-day transit is read for day-to-day mood and timing, which is why Panchang and Choghadiya work at that scale. Mercury, Venus and Mars change sign in weeks to months. Jupiter takes about a year per sign and Saturn about two and a half, which is why those two dominate discussion of longer life phases.

Rahu and Ketu always move in apparent reverse and stay about eighteen months in a sign, always exactly opposite each other.