Konark Sun Temple is a 13th-century Sun Temple at Konark in Odisha, India. It is believed that the temple was built by king Narasimhadeva I of Eastern Ganga Dynasty in 1255 AD.
The temple complex is in the shape of a gigantic chariot, having elaborately carved stone wheels, pillars and walls. Inside the temple resides a sundial, which people still use to tell time from to this day.
According to YouTube user Phenomenal Travel Videos:
The sundial has 8 major spokes that divide 24 hours into 8 equal parts, which means that the time between two major spokes is 3 hours. There are 8 minor spokes as well. Each minor spoke runs exactly in the middle of 2 major spokes. This means that the minor spoke divides the 3 hours in half, so the time between a major spoke and a minor spoke is an hour and half or 90 minutes.
Now, at the edge of the wheel, you can see a lot of beads. If you observe carefully, you can see that there are 30 beads between a minor and a major spoke. So, the 90 minutes are further divided by 30 beads. This means that each bead carries a value of 3 minutes. The beads are large enough, so you can also see if the shadow falls in the center of the bead or on one of the ends of the bead. This way we can further calculate time accurately to the minute.
The sundial shows time in an anti-clockwise fashion. At the top, the major spoke stands for midnight and this spoke stands for 3 A.M and this one for 6 A.M and so on. When I place a finger or a pen at the tail of the animal in the axle, the shadow will fall on the edge of the wheel. Now, I simply note the bead where the shadow falls. Using the math we did before, I can easily tell the current time precisely down to the minute. Imagine how much time and coordination would have happened between the astronomers, engineers and sculptors to create something like this 750 years ago.
The video below further explores how the dial works, and gives us a closer look at its beautiful intricacy and detail.