Equatorial or Universal Sundial

As the name suggests equatorial or universal dials is flexible to use any place in the world. It is built such a way that you can adjust the dial according to the latitude reading of your place of living. This kind of dial is also adjustable in southern hemisphere of the world.

Almost all the sundials are made to use for northern hemisphere. But, if you are living in Brazil, Australia or New Zealand than you are living in southern part of the world. In that, case using a equatorial sundial would not be problem at all.

You may probably heard about equator which is a imaginary line extend from east to west and splitting the world apart in two parts, namely northern and southern hemisphere. This equator line was drawn by imagining that the whole world is plane surface, just like the computer screen you are sitting in front now.

But,the world is not a plane surface, it is like a big ball. And if you draw a line from a center of the north pole to the centre of the south pole, it become the axis of the earth on which it spins every day. The earth slightly tilted on its axis. Celestial equator is the same imaginary line like equator but as it is drawn on the spherical original tilted world, so it get inclined by 23.4 degree with the equator.

When using a equatorial sundial, the one problem an user can face is that it will not world when the sun is on that celestial equator. Because at that time the sunlight falls on the edge of dial and the gnomon cannot cast any shadow to measure time on the dial.

Analemmatic Sundial

Analemmatic sundial is a type of sundial based on movable gnomon where other sundial use a fixed gnomon.They are not suitable to built in a small place; rather it require a large lawn. That's why this type of sundial are not very common through the world.

The name Analemmatic sundial came from the word called Analemma. The dial is elliptical and gernerally six meters wide in the middle; the short axis of the ellipse is alighed North-south and the long axis is aligned East-West. THe hours indicators are pointed from 6am to 6pm and the 12 hrs point directed towards true North.

On these sundials, hours marked by points at the edge of circumference of a elliptical dial. This is also very uncommon because, other types of sundials uses marked lines to indicate hours. The gnomon is vertical and should be moved according to the indicated place inside the elliptical dial on different seasons of a year.

Here is a fun that a person can stand on those marked point inside the dial at any given month of the year and act like a gnomon. So, these dials are very entertaining for people when they are placed inside any public amusement facilities as the visitor can interact with the dial by acting like a gnomon.

Why Sundial Time is Slightly Different than Normal Cock

The solar time was well defined in the equation of time presented by Ptolemy about two thousands year ago. The equation analyze the earths motion on its axis and around the sun in different period of a year to measure time. The equation was a subject matter of Astronomers until recently.

Ancient people used sundial to measure time until the last centuries invention of mechanical clock take over timekeeping from sundial. Although modern people do not use sundial to keep time but they use to buy or collect sundials as a matter of curiosity and antiquity. They observe the difference between the sundial time and their clock time and the issue of the Ptolemy's`s equation of time came in light again.  

The earth is rotating on its own axis and it is spinning around the sun as well. It takes approximately 365 days or a year for the earth to finish it`s full orbit around the sun , and this path is not circular it is elliptical. So, the earth come close to the sun for several months in a year and according to Kepler's law the spinning motion of earth on it`s axis become faster during this time. This phenomenon influence on a major measurement our clocks are based on, that is it counts the day with 24 hours. But, when  each spins very fast at that closer time to the sun, it actually spins around its axis less than 24 hours.

That make a lot of difference between time when we measure it upon solar basis and and measure it upon a regular clock basis. Scientists estimated that the difference become 14 minutes in Mid-February and just over 16 minutes in mid November. On the other hand, when earth gets further than the sun , it takes a bit more than 24 hours to finish a spin on axis or meridian. So, the clock gives us a average time all over year which is roughly 24 hours; but it is not totally accurate. But, it works as  the minor change does not give any  significant effect on our daily life.

What is Sundial?

A sundial is the ancient form of a clock used by humankind. The simplest sundial is a stick stuck in the ground, casts a shadow indicating the time.

If you asked time to a stone age human, they can differentiate time in two entities: Day and Night. Obviously they cant tell you what`s the exact digit of time because they don't have numeric sense or perhaps clock was not invented. However, it is clear that the sun rose and sets over the horizon. It's a fact that the shadow, the sun made its way across the sky has not escaped the attention of primitive man. The morning shadows were long, gradually decreased to disappear at lunchtime, then spread again in the opposite direction, behind the sun.Thus,shadow is a natural instrument for measuring time.

Using the shadow sun cast on the objects of earth, first clock was made in human history. No one can be sure that when the sundial was found, but we know that already in 3500 BC; The Egyptians built sundials not only maintained telling time, but it pointed time during the longest and shortest day of the year.

Sundials are usually with a circular disk used as face of a clock, On this disk, the lines use to curve down to represent the hours. There are also special sundial that can track the tides, the seasons and earthquake. In a sundial, obelisk is a gnome stands in the middle of clock disk that acts by casting shadow to mark time. In the northern hemisphere as the sun moves across the sky, this shadow moves clockwise. At lunch time, the shadow disappears which indicated noon or 12 hrs in our normal clock.

To compensate for the tilt of the earth on its axis,sundials are tilted to the north. Otherwise, the sundial will not compensate for slightly different way from the sun in the sky takes each day as the Earth moves through the seasons. Sundials are inclined to the north,called styles. These sundials are more acquarate because of its orientation is similar to the tilt of the earth, the hours remain the same all year round.

In English we use the word "hour" to tell time. This word can trace back its origin with the invention of sundial in Egyptian and Greek history. The word Hour comes from Greek or latin word Hor. The word Hor comes from Egyptian God Horus who was the God of Dawn.

In modern world, technology have gone so far to measure the time: mechanical clock, digital clock, atomic cock etc. But sundials still remains the most accurate time measurement, even after the invention of those clocks. People still use sundials to reset the times of clock invented by modern technology. However, with the invention of  Rolex!!!, sundial finds its place in gardens of modern society.

Pocket Sundial

We are using wristwatch now a day to keep a look at time in every day life. But, the history of  innovation of this miniature clock was not so smooth. During the time of it`s first development, wristwatch was facing lots of difficulty in accuracy for mechanical backlogging. It takes time to make a wristwatch with supreme perfection and became what it is now today.

The development of mechanical wristwatch began at Renaissance periods while Europe became increasingly trade oriented and business booms demands a accurate time time keeping device. Businessman and and traders movement becomes intense and they require a potable watch; but the armature mechanical watch cant satisfy their need. This continual pressure pressed the watchmaker to think of a different technology rather than blindly rely upon mechanincal technology to invent a potable clock.

What they came with is a millennium old technology of time-keeping: sundial and they perfected it to a pocket sundial. Since, the innovation,  pocket sundial become a very popular instrument collected by trader, craftsman and elites of European society. During earlier stage, those pocket sundials could be used only during day because sundial depends upon sunlight to measure time from shadow casted by it`s gnomon.

The Swiss watchmakers later perfected this pocket sundial usable during night as well in streetlights, gas lamp and even with a cigarette lighter. As it become more and more popular in Renaissance Europe, Pocket sundial become available for ladies and it became more as jewellery item than timepieces.The mechanical wristwatch also perfected after few decades and market domination of pocket sundial got gloomy.

Now a day, people uses pocket sundial as a instrument of antique and curiosity. These sundials are generally made of copper and brass and come up with built-in magnetic compass to be oriented north. The gnomon of this dial cast a shadow in sunlight and marks the local time by in the dial marked with 1 to 12 hrs. Some are ornamented with different designs and very handy with average weigh of 85 grams.

Think of a New Ornamental Meterial for Your Garden

You may have watched movies showing ancient greek and roman civilization. Then, you may notices the elegence home gardens maintrined by those two great civilization. They were sofisticated enough to decorate gardens with stone sculptures, water fountain and one item your eyes may negelect to notice; it is sundial.

Sundial is the oldest time showing device used by human civilization. Historians noticed that there were aroud 13 different types of sundial used by the Greeks and Romans untill 30 BC. Although sundial was rarely used by the Greeks around 1500 BC; the Romans practices it use for a mass population in the areas they ruled.  Roman Emperors emphesised the use of sundial in various public places and events.

You may have heard the term "English Garden" if you travel in Europe. English Garden is the concept of grdening around Europe in 18th century inspired by lanscape painting of Nicolas Poussin and Claude Lorraine. The concept of English Garen was a standadized practice of public parks and estate home garden all over europe in the 19th century. Sundial was an imprtant antique as grden furniture in the concept of English Garden. Nevertheless to mention the 19th century ornate carved stone sundial .

There are different types of sundials available today; to ornement home garden. Among these, most polpular ones are horizontal sundial, brass armillary, ornate curved stone, ornamental astrolabe etc. It is important to notice that sundials can be percieved as balacnces and beautiful addition for a fairy garden rathen than a official time keeping device. As, it is based on solar time and need to be adjausted thoughout diffrent seasons in a year.

Make a Sundial from a Flower Pot

There could be hundreds of way to make a sundial from the scrap. All those methods may require some tools or materials to collect which could not be handy for everyone. What about making a sundial form a object that is available in most of houses.Lets make thing simplified, making a sundial just form a flower pot.

Making a sundial from a flower tub is a fun for the kids and educational in a way top learn the earth circular rotation around the sun. They could easily made this sundial from simple astrological experiment in the meanwhile inventing most ancient piece of time telling device.

Things to do before you start

Find out a flower pot in your home garden. Wash this by taking away any plant or soil inside it. If it is a hassle for you, buy a new one from the market. Manage a straight long dowel or pen that will work like a gnomon up above the pot. You also need a marker pen, white paper and tap.


1. Go out side ; find a sunny spot in your garden or yard. Place the white paper on the ground and put the pot on the paper upside down.

2. Make a hole at the center bottom of flower pot and stick the dowel or straight pen inside it. Make the dowel permanent by gluing it though the hole. This will make the dowel permanent on the tub and remember it need to stand as straight as possible.

3. Now check you wrist watch and exactly each hour notice the shadow of dowel casted on white paper. Use a marker pen to draw a line corresponding to each shadow in every hours of a day.

4. If you start this process in the morning near the evening you will end up with around 8 to 10 line drawn on the paper indicating hours of the day; e.g. 9 hrs, 10 hrs, 11 hrs etc.

When you finish it, you will see the lines you draw on the paper follows a clockwise direction. This is because if you live in the northern hemisphere, any shadow casted by sun will move clockwise. Shadow will also change it places as the earth is not stable relative to sun; it is spinning on its axis continually.
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