Your rising sign (lagna) and how exact it is
Your Vedic ascendant (lagna) and its degree from your birth time and place, with how many minutes of birth time would change it.
Your birth details
Also worth asking
What is my ascendant (lagna)?
Your ascendant, or lagna, is the sidereal sign rising on the eastern horizon at the moment and place of your birth. It sets the twelve houses of the chart, so it changes every two hours or so: an accurate birth time matters more for the lagna than for any planet.
How Patri works it out
- The ecliptic point rising at your place and time (DE440 positions, Lahiri ayanāṃśa).
- The historical clock time at your birthplace on that date (IANA time zones with their history; local mean time before 1906 in India).
- How many minutes earlier or later the rising sign would change, and whether your stated precision covers it.
Sources: Bṛhat Parāśara Horā Śāstra, Ch.11 v.2 · Bṛhat Parāśara Horā Śāstra, Ch.7 v.37-38 · Narasimha Rao, Vedic Astrology, §7.2