The disagreement in one paragraph#
Tropical astrology measures your Sun sign against the seasons (Aries begins at the spring equinox, regardless of where the stars are). Sidereal astrology measures it against the fixed-star background (Aries begins where the constellation Aries currently is). Earth's axial precession has moved these two reference frames about 24 degrees apart since the systems were originally aligned ~2,000 years ago — so the same birth date gives you a different Sun sign depending on which zodiac you consult.
What K A X A N T A uses#
We use the tropical zodiac across all Western astrology calculations. This matches modern Western convention (Western astrology, as practised in Europe and North America for the past several hundred years, is tropical).
For Vedic / Jyotish readers: we do not currently expose a sidereal Lahiri-ayanamsa toggle. If that is what you need, other apps are better suited for you. We plan to expose an ayanamsa setting post-launch for users who want to compare both frames.
Why tropical is the right choice for our scope#
Two reasons. First, the vast majority of Western users who come to the app have only ever read tropical charts — switching them to sidereal would make every reading they have ever done suddenly wrong. Second, tropical aligns with the seasonal meaning of each sign (Aries = spring energy), which Western psychological astrology leans on heavily.
What to do if this changes your chart#
If you have been reading yourself as a sidereal sign for years and our tropical Sun sign disagrees, the right read is not "one is wrong." The right read is: "these are describing two related-but-different attributes of me." Tropical speaks to how your archetype relates to the seasonal wheel; sidereal speaks to where the physical stars were in the sky when you were born. Both can be true.
If this bothers you, the Architect chat is a good place to explore it — ask it to map the overlap between your tropical and sidereal readings and it will walk you through which traits it weights more heavily for each.