Rasmus Jonassen Sørnes (22 March 1893 – 15 February 1967) was a Norwegian inventor, clockmaker and radio technician, and is most famous for his advanced astronomical clocks, the most precise of which has an inaccuracy of 7 seconds during 1000 years.

[1] During his lifetime, Sørnes also designed and built a large variety of agricultural, radio-technical and mechanical devices, only a few of them patented.

[2] Rasmus Sørnes was born in Sola in Norway on 22 March 1893 from a mediocre background, his parents were farmers with limited resources.

After finishing elementary school, Sørnes applied to be a watchmaker apprentice in Stavanger, but was rejected on the grounds that he was a farmer son with big hands and lumpy fingers.

Sørnes was a man of modest education, but he was self-taught in a variety of scientific trades and technological disciplines, including advanced mathematics, physics, and astronomy.

In 1910, he designed and built a four-stroke combustion engine complete with electric ignition and water-cooling system and he constructed a turbine power plant.

While commercial industry was uninterested in this feature for the lifetime of the patent, this has in modern times become standard in loudspeaker design.

In the midst of the Great Depression, unemployment was high and the entire staff had few options but to move along with their employer.

During World War II, Sørnes built another radio transmitter for the purpose of clandestine communication, based on his earlier device.

The radio he built during the war, was later described as "a masterpiece of technical elegance and intelligent camouflage" by historians.

[4] He designed the first automatic model railway in Norway, which was used in a shop window exhibition, and a solar-cell-powered radio-controlled engine for lighthouses.

[6] Although trained as an electrician and employed as a radio technician, watches and clocks were a source of lifelong fascination for Sørnes.

In the 1937 Sørnes constructed his first astronomical clock, showing standard and Greenwich time, all solar and lunar cycles and phases, the Julian calendar, high and low tides, and sunset/sunrise.

The accuracy of the celestial orbits suffered as the calculations were based on regular calendars without full correction of the irregularities.

1, Sørnes wanted to be able to run his clocks forwards and backward in time to examine previous and coming events.

Rasmus Sørnes steadily kept improving his design and adding even more features, and in 1954, the 3rd clock was finished.

The gear trains from the two previous clocks have been revised for improved accuracy, several correction works have been added to make up for irregularities in the celestial orbits, and most importantly, the precession of the equinoxes has been taken into account.

The large dial in the middle of the front has a fixed Zodiac and two hands showing the position of the Sun and the Moon on the ecliptic circle.

The principal design of gear trains and transmissions is similar to Sørnes' fourth and final clock, arguably the most complicated of its kind.

4, also called "the Sørnes Clock" (Norwegian: Sørnesuret)[7] is a magnificent fusion of art, craftsmanship, and electromechanical technology, engraved and with gold and silver plating.