The tropical zodiac
The tropical zodiac starts at the March equinox and divides the ecliptic into twelve equal thirty-degree signs. It is tied to seasonal reference points, not the uneven borders of astronomical constellations. Asteria’s calculations use this system.
The sidereal zodiac
Sidereal systems anchor signs to a stellar reference using an ayanamsha. Several conventions exist, including Lahiri. Vedic astrology commonly uses a sidereal zodiac alongside techniques such as nakshatras and dashas. A tropical chart is not interchangeable with a sidereal chart.
Choosing a tradition
Both traditions have long interpretive histories and internal disagreements. Learn the assumptions of one system before mixing techniques. Asteria teaches these differences but does not currently calculate a sidereal chart or dasha schedule.
Keep exploring
Study the vocabulary and traditions in the AstroWiki reference. Astronomical calculations use Astronomy Engine. Interpretations are original Asteria editorial content and are not scientific predictions.