Coming over a blind rise on the farm Goellschau, 100km southwest of Windhoek, one is faced with an unusual sight. Four enormous steel structures against the mountains on the horizon. Set in a 2 400m2 square and linked to a control room, they form a world-class telescope. The site is home to the High Energy Stereoscopic System (HESS) project, run by Germany’s Max Planck Institute of Nuclear Physics.
The structures support dishes that are each plated with 378 parabolic mirrors and are more than 12m in diameter. They reflect the light of high-energy gamma rays entering our atmosphere 10km up in the sky. The flash is captured by a high-resolution camera and sent to hard drives in the control room for later analysis. After scouring terabytes of data, astronomers can draw conclusions about the galaxy by studying the density and duration of the flash of the gamma ray.
Cattle farmer Joachim Cranz has been no stranger to diversification since he took over the family farms, first Isabis and later Goellschau. He gains an income from day tours, self-catering, hiking, the occasional trophy hunter and by selling off game. His wife Adele is considering breeding horses for endurance racing. “And we have a 4×4 trail and a campsite,” he adds. “It doesn’t generate spectacular income, but it makes nice grocery money.”
But the telescopes aren’t your run of the mill operation, he admits. “The data that’s gathered here leads to all kinds of conclusions on black holes and the existence of the universe. It’s actually quite amazing.” A long relationship A ccording to HESS, the four Cherenkov telescopes on Goellschau are in a unique position to monitor the southern skies, as there is no light interference and skies here are clear for most of the year. The mild, dry conditions and the altitude (1 800m above sea level) also guarantee minimal temperature variation around the sensitive equipment.
“Those conditions brought astronomers to the Gamsberg area decades ago,” recalls farmer Joachim Cranz, whose family has found a lucrative partner in the stargazers. I n the early 1970s, the Max Planck Institute approached Joachim’s father Juergen to set up an observatory in the area. Juergen bought 240ha of the Gamsberg from a local farmer, who had little use for the plateau. For the astronomers, however, it was prime real estate. In fact, a conglomerate of scientific institutes wanted to make it home to the biggest observatory on this side of the equator.
But the apartheid government wasn’t a fashionable partner, and the project went to Chile. The observatory was operational `til the mid-1980s. At the turn of the century, the Germans took a renewed interest in the Gamsberg as a potential site for their HESS project. They rekindled their relationship with the Cranzs, and this time Joachim and his brother Stephan negotiated on behalf of the family. “We sat around this same veranda table and explored options,” says Joachim, who was then a management consultant in Windhoek. “The original site on the plateau was ruled out as impractical, and they were basically looking for a reliable landlord.”
The Cranz family, originally from Germany, settled on their farm Isabis three generations ago. At the time of the negotiations, Stephan lived on neighbouring Goellschau, which Juergen bought 40 years ago. It was decided to build the telescope there and so a 200ha area was leased for R57 000/year for a minimum of 10 years. Construction started in 2000 and by 2003 all four telescopes were up and running. Research institutes from eight affiliated countries and over a hundred researchers were making groundbreaking discoveries.
All eyes to the telescopes A year ago, Joachim took over the farming operations on Goellschau, after his brother tragically passed away. “Obviously the rent for the actual site goes to my sister-in-law until the scientists have all the data they need, and dismantle the telescopes in 20 years or so,” he explains. “But with the lease of the farming operations we became responsible for the yearly service contract.” The contract entails the service of the buildings and grounds that the HESS partners use, supplying water, grading the roads, housekeeping and reservation services, security and bookkeeping.
All in all, it earns the Cranzs a lump sum of about R250 000/year. “It comes nowhere near the amount involved with ranching, but it makes a nice side income,” says Joachim. He’s quick to stress that the actual net profit per year will differ. “If for instance we have heavy rains, we’ll have to spend more money on road maintenance.” The site itself is impressive. “You don’t grow those boys that easily,” astronomy professor Carl Akerlof, who is visiting from the University of Michigan and is a veteran in gamma ray research, says of the telescopes.
He points to a concrete circle in the middle of the square formed by the telescopes. “A fifth mirror will be installed here soon, about 2,5 times the size of the other ones, which will boost the capacity significantly.” Prof Akerlof, who uses an optical telescope on the site, is happy with HESS’s arrangements with the Cranz family. “If you talk about favourable conditions for observing the galaxy, it just doesn’t get any better than this,” he enthuses. A new group arrives at the crew building, just out of sight of the telescopes. The researchers stay in a clean, spacious building equipped with luxuries such as DSTV and table tennis. With so many researchers involved in the project, picking up the scientists from the airport and making sure they get all their supplies from Windhoek takes some coordination.
“That’s also part of our service, making sure the groups are settled in for the three-week moon cycle,” says Joachim. Back at the telescopes, Joachim has cleared paths for the builders, technicians and astronomers, which are marked with white stones because the telescopes are so sensitive a torch is out of the question. “If you light so much as a cigarette, the system shuts down and it becomes a very expensive night,” warns Joachim. He admires the scientific ingenuity his family has contributed to over the years. “The electric motors for the adjustment of the mirrors are window-winder motors from the automobile industry,” he says.
“They were the only ones that were watertight over a long period.” In the fading light he looks up to one of the telescopes. A couple of hours from now the sentinels will awaken, point their cameras to the skies and start their search. By then he’ll be travelling to Windhoek – under one of the most beautiful starry nights in the world – to attend a farmer’s workshop the next day. A farmer’s work is never done. Contact Joachim Cranz on +264 62 57 21 33, cell: +26481 1245588, e-mail [email protected], or visit www.isabis4x4.com. |fw