Many of us are aware of Sun Dials.
Sun Dial, Konark,India.
Many would have visited the one at New Delhi.
But how does one calculate Time with the help of a Sun Dial?
Take the famous Sun Dial at Konark, Odisha, India.
There are eight spokes in the Wheel.
‘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.
Now if you are observing closely, you would have 2 questions in your mind right now. The first question would be, what happens when the sun moves from east to west. Since the wheel is carved on a wall, the sun would not shine on this wheel at all. How can we tell time in the afternoons? Now, the Konark temple has another wheel or sundial, located on the west side of the temple as well. You can just use the other sundial that will work perfectly from afternoon, until sunset.
This is the second and the most interesting question. How do you tell time after sunset? There would be no sun, and hence no shadows from sunset till the next morning’s sunrise. After all, we have 2 sundials in the temple which work only when the sun shines. To this question, I want to point out that the Konark temple does not have just 2 wheels like this. The temple has a total of 24 wheels, all accurately carved just like the sundials. Have you heard of the Moondial? Do you know that the moondials can work just like sun dials during night time? What if the other wheels in the temple could be used as moondials?
Many people think that the other 22 wheels were carved for decorative or religious purposes and do not have an actual use. This is what people thought about the 2 sundials as well. Believe it or not, people thought that all the 24 wheels were just carved for beauty and as Hindu symbols. About 100 years ago, it became known that this was a sundial when an old yogi was seen calculating time secretly. Apparently selected people were using these wheels for generations and for 650 years no one else knew about it. They say that when they asked him about the purpose of the other 22 wheels, the yogi refused to talk and simply walked away.
And our knowledge of just these 2 sundials themselves is actually very limited. You can see how there are multiple circles of beads. You can see carvings and markings all over these sundials, and we don’t the meaning of most of them. For example, this carving on a major spoke has exactly 60 beads. Notice how in some carving you can see leaves and flowers which may mean Spring or Summer. Notice how in some carvings you can see lemurs mating, which only happens during winter. So, these sundials could have even been used as an almanac for a variety of different things. Now you can understand how limited our knowledge is about the rest of the 22 wheels.
Notice that there are clues on these wheels that people have overlooked for centuries. Notice how a woman wakes up and looks at a mirror in the morning. Notice how she is stretching, being tired and ready to go to sleep. And you can also see that she is engaging in sexual activity during night. For centuries, people have ignored these hints and thought that these were carvings of Hindu Goddesses.
This is also a perfect example of how people think ancient unexplainable carvings are just for beauty or religious purposes. If ancient people spent a lot of time creating something, there is a very good chance that it was done for a valuable, scientific purpose.
Moondials are time pieces similar to a sundial. The most basic moondial, which is identical to a sundial, is only accurate on the night of the full moon. Every night after it becomes an additional (on average)[note 1] 48 minutes slow, while every night preceding the full moon it is (again on average) 49 minutes fast, assuming there is even enough light to take a reading by. Thus, one week to either side of the full moon the moondial will read 5 hours and 36 minutes before or after the proper time.
More advanced moondials can include charts showing the exact calculations to get the correct time, as well as dials designed with latitude and longitude in mind.