Cazimi means the planet is in the heart of the Sun.
William Lilly, writing in Christian Astrology in 1647, set the orb at 17 minutes of arc on either side of the Sun's center.
That number is not arbitrary.
It comes from the apparent radius of the Sun's disc plus a small allowance.
A planet inside 17' is, from Earth's view, sitting on the solar disc.
Lilly called this state the most fortunate position a planet can occupy.
Modern astrologers sometimes tighten this to 16'.
Bonatti, in the 13th century, gave different figures depending on the planet.
Our API takes a single boolean intent: which tradition do you want.
The preset switches the orb.
A true_cazimi flag fires when the conjunction is exact within a few arc-seconds, which traditional astrology treats as a separate, rarer event.
Mercury and Venus cazimis happen multiple times a year because they orbit close to the Sun.
Mars cazimi is a once-every-two-years event.
Jupiter cazimi happens roughly once a year.
Saturn cazimi once a year.
Each one is a date worth knowing.
Lilly: 17' of arc. Modern: 16'. Bonatti: planet-specific.