VietNamNet Bridge – The design of a solar clock in Bac Lieu Province, in south Vietnam, is unlike any other sundial in the world.

This unique clock, located in the Continuing Education Center in Bac Lieu City, is over 100 years old.

“Thai Duong” clock (Sun clock) was set up in front of Bac Lieu Governor’s house during French colonialism. The creator of this clock was Mr. Luu Van Lang (1880 – 1969), a famous scientist of the South in the early 20th century.

The clock has fairly rudimentary structure, with the surface facing East. It is made with brick and cement, about 0.7 meter high and 1 meter wide. The dial is an inclined cross section, and a vertical rectangular piece protrudes in the middle.

Twelve Roman numbers were hand-carved on the dial, from 1 to 12 to indicate hours. The middle of the numbers is divided into 12 areas to indicate minutes.

The operational principle of this clock is simple. Sunlight shines on the rectangular surface which creates a shadow mark on the dial. Time is determined based on this trail.

The shadow of sunlight on the clock rotates clockwise, in the same direction with the common clock, therefore, in this image, the hour is 10.

The “minute hand” is located between line 8 and 9 in 12 minute lines of 10th hour. Each minute line equal 5 minutes, so minute in this picture is 8,5 * 5 = 42,5 minutes. In fact, when the picture was taken, the camera’s clock was 10.39am. Thus, the error of the solar clock in this case is approximately 3 minutes.

As a rudimentary clock, the accuracy is quite impressive.

The biggest drawback of the solar dial is its “operation” by the sun, so the clock will “die” on dark or cloudy days.

Reds.vn