This week’s column concerns me a little because it’s about science. It may be too geeky for some, and not geeky enough for geeks. It’s a difficult line to walk, but let’s try.

King Kalakaua loved technology. Many in Hawaii know he met with Thomas Edison on his around-the-world travels in 1881, and brought electricity to Iolani Palace four years before the White House had it.

However, few may be aware that he and Hawaii played a role in our understanding of the size of the solar system.

The story began in 1874, just months after he was elected king. At the time, scientists understood the placement and relative distances of the sun and planets.

The problem was that they didn’t know how far apart the sun, moon and planets were from each other. The earth and sun are 93 million miles apart, but in the 1870s, when Kalakaua was king, the estimates were between 55 million and 81 million miles apart.

The Transit of Venus in 1874 presented an opportunity to calculate that distance. A “transit” is when one astronomical body passes in front of another.

On Dec. 8, 1874, Venus was predicted to pass across the body of the sun, as seen on Earth. Scientists realized they could observe and time this event from different places on Earth and use those observations to calculate the distance of the sun and planets.

Venus would cross the face of the sun at slightly different times for different observing stations. By knowing the distance between, say New Zealand and Hawaii, they could use geometry to ascertain the size of our solar system.

This was made possible by Capt. Cook, who nearly 100 years earlier had calculated Hawaii’s exact longitude and latitude using observations of Jupiter’s moons, says University of Hawaii astronomer Michael Chauvin.

On Sept. 9, 1874, “nearly a century after Capt. Cook had appointed Hawaii a position on a map,” Chauvin says, “a ship from England, the HMS Scout, sailed into Honolulu Harbor carrying an expedition of seven astronomers.”

Their mission: observe a “rare transit of Venus across the sun for the purpose of better determining the value of the Earth-sun distance, and thereby the absolute scale of the solar system.”

Chauvin wrote about this in his book “Hokuloa: The British 1874 Transit of Venus Expedition to Hawaii.”

The observers arrived in Hawaii with an estimated 93 tons of materials, including telescopes, clocks, chronometers, photographic chemicals, tools, bedding, food and seven types of alcoholic beverages.

They set up shop in three locations in Hawaii: one in Kailua-Kona, one in Waimea, Kauai, and the last in Honolulu, mauka of today’s Waterfront Plaza (once known as Restaurant Row), about where the court building is. Back then the area was called Apua.

King Kalakaua took an active interest in the program. “It will afford me unfeigned satisfaction if My Kingdom can add its quota towards the successful accomplishment of the most important astronomical observation of the present century,” the King said, “and assist, however humbly, the enlightened nations of the earth in these costly enterprises to establish the basis of astronomical distances.”

The scientists were well taken care of in Hawaii. They stayed at the Hawaiian Hotel downtown. King Kalakaua visited often and sent his band to entertain them many evenings. He threw lavish balls for the astronomers, and they met Princesses Ruth, Bernice Pauahi, Miriam Likelike, dowager Queen Emma and many others.

Clouds obscured the station in Kailua-Kona, but Waimea and Honolulu recorded the event at 3:35 p.m. Dec. 8. Nine stations around the world were set up to observe the transit as part of the British project.

The data took three years to calculate, but in 1877 the team reported their estimate that the sun is 93.3 million miles from the earth. They were off by less than one-half of 1 percent.

What the Hawaiian Gazette called the “astronomical event of the century” was a success, and Hawaii played a major role in it.

Transits of Venus are rare, but the next one is Tuesday. It won’t happen again until 2117.

The UH Institute for Astronomy will set up telescopes equipped with special solar filters for public viewing on Waikiki Beach, at the Pacific Aviation Museum on Ford Island and at Ko Olina near Lagoon 4 from noon until dusk. The institute will also distribute free “solar viewers” that will allow individuals to look at the sun safely.

For details on these and other locations for viewing the transit, visit www.ifa.hawaii.edu/transit.

Bob Sigall, author of the “Companies We Keep” books, looks through his collection of old photos to tell stories each Friday of Hawaii people, places and companies. Email him at Sigall@Yahoo.com.