Why the Moon and not the Sun
The Sun moves roughly one degree a day and stays in a sign for about a month, so it describes the broad season of a life. The Moon crosses a sign in about two and a quarter days, which makes it the natural marker for anything that changes daily.
In Jyotish the Moon also governs the mind and the emotions — manas. A daily reading is a description of the emotional weather, so the Moon is the sensible reference point.
The sidereal zodiac and ayanamsa
Vedic astrology uses the sidereal zodiac, measured against the fixed stars. Western astrology uses the tropical zodiac, tied to the equinox. Because the Earth wobbles on its axis, the two have drifted apart by roughly 24 degrees over the last two millennia.
That offset is the ayanamsa, and it is why a Western Aries is usually a Vedic Pisces. We apply the Lahiri (Chitrapaksha) ayanamsa, the standard adopted by the Indian calendar reform committee.
What a daily reading is actually built from
A forecast here is not written to a template. It is assembled from where the transiting planets stand right now relative to your Moon sign — which house each one occupies counted from the Moon, the aspects they cast, the nakshatra the Moon is passing through, and the Vimshottari dasha period currently running in your chart.
Gochara — transits from the Moon
Gochara is the study of transits counted from the natal Moon rather than from the ascendant. A planet is judged favourable or difficult by the house it occupies in that count: Jupiter is welcome in the 2nd, 5th, 7th, 9th and 11th, while Saturn is felt most in the 1st, 4th, 7th, 8th, 10th and 12th.
Sade Sati
The period most often asked about is Sade Sati — the roughly seven and a half years Saturn spends transiting the sign before your Moon, your Moon sign itself, and the sign after. It is traditionally a demanding stretch rather than a disastrous one, associated with responsibility, consolidation and slow, durable gains.
Dasha — the timing layer
Transits describe the present weather; the Vimshottari dasha describes the climate. The 120-year cycle assigns each planet a period whose length is fixed, and the one running at your birth is set by the nakshatra of your Moon. The same transit can read very differently depending on which dasha it lands in.