Botjes planetarium

Botjes Planetarium
1992 Newspaper report: arrival at Calvin College
Previous Home


Grand Rapids Press, Monday, May 18, 1992

Calvin's gift planetarium is on display
By Marc Schulhof

Clarence Menninga speaks very little Dutch. But because science is a universal language, the retired Calvin College professor has been able to restore a small planetarium built in the Netherlands in the mid-19th Century.

The planetarium was donated to the college by Henry and Bertha Bos in 1989. In a ceremony today, the gift was to be officially accepted and placed on display in North Hall on the Calvin campus.

The instrument was built by Wildrik Botjes, a watchmaker and goldsmith. Botjes spent 20 years building two planetaria at his home in Woldendorp in the Netherlands.

According to Menninga, Botjes' planetaria show not only the position of the planets - with extreme accuracy - but also the date, time of day, sunrise and sunset times, true and average time, and other more esoteric information.

In 1868, Botjes gave one of the eight-sided glass-and-wood instruments to his nephew, Botje Bos.

When Bos moved to America in 1896, he took the planetarium - which is about one foot high and three feet in diameter - with him. Sometime later, he passed it on to his son, Hinderikus Bos.

The younger Bos kept the instrument in good repair, and in 1926 it won first prize at an exhibit in Kalamazoo, where Bos lived.

In 1968, Hinderikus Bos gave the planetarium to his son, Henry Bos. Though it was still operational at that time, it stopped running soon after.

Twenty years later, Henry Bos decided to donate the museum-quality instument to the college.

"The family recognized that there was some value in the instrument," Menninga said, "but they didn't have the time to keep it in operating condition. They are very enthusiastic supporters of Calvin. They had four kids, and all attended the school."

The second planetarium Botjes built, Menninga said, is currently in a museum in the Netherlands.

Menninga started the restoration last fall. He began working on it full-time about six weeks ago.

"I tried as much as I could to keep the original materials, construction and paint," he said. "The changes that I made are the result of wear to the clock mechansim."

Menninga taught geology at Calvin College for most of his 25 years. In 1983, when the college established a department of Geology, Geography and Environmental Studies, he was named its chairman. He remained in that position until his retirement in 1990.

For the last two years, he has taught occasionally, worked on projects and acted as the science department's radiation safety officer.


Previous History of the Botjes Planetarium
Home Botjes planetarium home page


Transcribed 9/2/03 by Larry Molnar