Reckoned from the sky
The leap year comes from the instant the sun crosses the equinox on the 52.5° E meridian, not from an approximate table. The same engine that runs the apps built this page.
Zij
About us
The Persian calendar that reckons from the sky
Why another calendar?
Every occasion has a source
For every day you see where it came from, how well attested it is, and where it is an official holiday. Nothing is anonymous.
It asks nothing of you
No account, no tracker, no analytics. The apps work fully offline from the first launch, and this site runs without cookies.
The story
1The name
A zij was the astronomical table the old astronomers reckoned the calendar from — from the Ilkhanic Zij of Maragheh to Ulugh Beg’s in Samarkand. This product does the same job: an exact calendar, from the sky.
2The mark
A calendar leaf, and on it the letter “ز”: its stroke is an orbit and its dot a brass sun. The default palette, “Twilight Meridian”, takes its name from the 52.5° E meridian where the turning of the year is computed.
3The engine
One Rust engine, written once, running on iPhone, Android, the web and Chrome. The leap year from the astronomical equinox, the lunar month with four criteria, every occasion from an open package with sources. This very page was built by the same engine.
4Three pillars
Accurate: it reckons from the sky. Your choice: no package is on by default and every occasion can be hidden or changed. Respectful: no account, no tracker, offline from the first launch.