All three AstroSutra tiers use the same Swiss Ephemeris (NASA JPL) backbone with Lahiri Ayanamsha — there's only one astronomical engine. What changes between tiers is the depth of computed output and the breadth of AI-narrated interpretation layered on top.
Pricing is geo-localised — see the live plans page for your region's amount in your local currency. Premier and Ultra unlock features and computation depth; they don't unlock different astronomy. The Free Moon Sign and Nakshatra calculators run on the identical engine that powers Ultra.
If you only need Ultra for a one-off decision (a job-change window, a marriage muhurta, a relocation question), the Day Pass gives 24 hours of full Ultra access, credited back if you subscribe within 48 hours. See how AstroSutra achieves classical-Vedic accuracy for the full BPHS computation stack.