For about 300 nights out of the year, Mauna Kea on the Big Island of Hawaii is one of the best places in the world for ground-based astronomy. At an elevation of 4,205 meters (13,796 ft), the summit sits above a large portion of the Earth’s atmosphere, and usually, the sky is clear, calm and dry. Indeed, 13 giant telescopes sit Mauna Kea’s summit, and they have made some of the biggest discoveries in astronomy. But for the remaining nights of the year, a variety of weather-related issues can keep astronomers from observing, and visitors from climbing to the summit to see those pristine skies for themselves, as well as being able to watch some of our biggest eyes on the skies action. Sometimes clouds, high winds or humidity might keep the telescope domes closed, other times snow can close the roads. On a recent visit to Hawaii, heavy snow kept the roads closed for three days and my long-planned trip to the top of Mauna Kea was, disappointingly, scrubbed. But I did get a great behind the scenes tour of the W. M. Keck Observatory headquarters in Waimea.
While the telescopes are up at at the top of the mountain, astronomers seldom actually work at the telescopes themselves. Instead they work out of remote operations offices at the headquarters in Waimea. There is an operations room for each of the twin 10-meter Keck telescopes: Remote Operations 1 works the Keck 1 telescope:
And Remote Operations 2 works Keck 2:
I arrived in the morning before any of the astronomers were there. “People who work for Keck help the visiting astronomers,” said Alexandra Starr, who works with the media and is a public information officer at the Keck headquarters. “Usually, the visiting astronomers start filtering in about 2 o’clock, and the people who work on the summit get things ready for what the astronomers want to observe. There is a camera for those down here to view how things are going for getting the telescope pointed exactly where they want it.”
But the domes on the telescope can’t be opened until the sun goes down.
“So, once they get everything set up, they go for an early dinner and then come back here and observe all night long,” said Starr. “We do have people working around the clock, however. For astronomers who have been here before, sometimes they don’t need a lot of assistance, but our support astronomers will help all the visiting astronomers get the best observing they can, and get the information they need while they are on the sky.”
About 125 people work full-time at Keck, of which two-thirds are local people from from Hawaii. With an annual operating budget of $11 million, the Observatory is one of the town’s largest employers.
At the headquarters, there are condos where the visiting astronomers can stay:
Most astronomers have just two nights for observing, and Starr said it can be up to a year and a half from when astronomers submit a proposal to use the Keck telescopes to when they actually get to observe. But sometimes, depending on the astronomer and what they are observing, they’ll get to return again fairly quickly when the weather doesn’t allow for observing.
“The past 2 nights we haven’t been observing, and those people are in town ready to go,” Starr said.
The backside of facilities includes the observatory’s own mechanics shop. “We have eight 4-wheel drive automobiles to get to the summit, and our own mechanic shop to keep them all in top shape,” Starr said.
The Keck Observatory’s headquarters in Waimea is open to visitors, and volunteer guides are available Tuesday through Friday from 10 a.m. to 2 p.m. to share information about Keck and the other Mauna Kea observatories. The visitor’s center also has a conference room for public lectures from visiting astronomers.
Inside are models and images of the twin 10-meter Keck telescopes:
The twin Keck telescopes are the world’s largest optical and infrared telescopes. Each telescope stands eight stories tall, weighs 300 tons and operates with nanometer precision. The telescopes’ primary mirrors are 10 meters in diameter and are each composed of 36 hexagonal segments that work in concert as a single piece of reflective glass.
Outside in the visitor center courtyard is a grassy area that represents the size of just one of the hexagonal segments, which are 1.8 meters (6 ft) in diameter.
Each segment weighs .5 metric tons (880 pounds), and are three inches thick. They are made of a glass and ceramic composite called Zerodur. Zerodur itself is not reflective, so they are covered with a thin reflective layer of aluminum.
“While the telescope is actually working it is constantly fine tuning the position of the individual mirrors to make sure they are all in alignment,” said our tour guide Rosalind Redfield.
On the telescope, each segment’s figure is kept stable by a system of extremely rigid support structures and adjustable warping harnesses. During observing, a computer-controlled system of sensors and actuators adjusts the position of each segment – relative to the neighboring segment – to an accuracy of four nanometers, about the size of a few molecules, or about 1/25,000 the diameter of a human hair. This twice-per-second adjustment effectively counters the tug of gravity.
Up at the summit, (which I can only share pictures provided by the Keck Observatory) Redfield said it is like the other side of the Moon. “Absolutely nothing grows up there, the elevation is so high it is completely barren,” she said. “There is fine, sandy type dirt, and they don’t like people driving up there as it stirs up dust. The paved road only goes so far, and anyone driving at the summit creates enough dust that it can cause a problem, and people are only allowed to drive up if you have a four-wheel drive.”
The sun sets on Mauna Kea as the twin Kecks prepare for observing. Credit: Laurie Hatch/ W. M. Keck Observatory
The two Keck telescopes and the 8.3 meter Subaru telescopes take the very top of the mountain. They are joined by the 8.1 Gemini North Telescope , the 0.6-m educational telescope, from the University of Hawaii at Hilo, a 2.2-m telescope University of Hawaii Institute for Astronomy, the 3 meter NASA Infrared Telescope Facility, the 3.6 meter Canada-France-Hawaii Telescope, the 3.8 meter UKIRT (United Kingdom Infrared Telescope), the 10.4 Caltech Submillimeter Observatory, the 15 meter James Clerk Maxwell Telescope, the 8X6 meter Submillimeter Array and the 25 meter Very Long Baseline Array.
But, no climb to the summit for me — not this time anyway! I hope to return one day to Mauna Kea to see first-hand where science and nature come together to allow for continued discovery of our universe.
For more information about the Keck Observatory, see their website, and if you are in Hawaii or going to be visiting the Big Island, find information here on how you can visit the Observatory headquarters, or go to the summit.