Birth details & your chart
How does Cosmuna calculate my birth chart?
Cosmuna computes precise planetary positions, ascendants, and house cusps using the Swiss Ephemeris (the gold standard in astronomical and astrological calculations). We support dual models: Western Tropical (Placidus houses) and Vedic Sidereal (Lahiri ayanamsha, D9 Navamsa, and Vimshottari Dasha) so you can view your chart through the lens that speaks most clearly to you.
What if I don't know my exact birth time?
When your birth time is unknown or approximate, Cosmuna creates an honest Blueprint focusing on what is astronomically certain (such as planetary signs and major aspects) rather than forcing artificial precision where it doesn't exist. You can update or refine your birth time at any time in Settings.
An approximate birth date first, honest details later? That's the usual path — change your date, time and place any time from your profile (You → Blueprint → change birth details in the mobile app, or Settings on the web) and every chart and reading recomputes from the new birth data.