With a few clouds drifting through the collection of white domes at the top of the Roque de los Muchachos peak, we drive up to the Grantecan to see how the cooldown is progressing. Working our way through some tourists visiting the world’s largest telescope, we head for the laboratory, where all through the night the refrigerant pump has been using helium to bring the internal temperature of the CanariCam infrared detector closer to the working target of approximately 8K.
The temperature detectors, monitored through software designed by team member Frank Varosi, show the steady progress of cooling down. The detectors are currently showing temperatures as low as 40K (-388 degrees Fahrenheit), slowly dropping after 25 hours of pumping.
Cold yes, but not nearly cold enough to allow the detector to find and count the few feeble photons making their way to Earth from cold debris surrounding a star 63 light years away, or sneaking through dust surrounding the center of our own Milky Way some 26,000 light years distant. Greg Bennett, the team engineer, adjusts a relief valve, watching the pressure readings, and the pump quietly whines away as the temperature slowly creeps downward.
The air is cool and dry at 7900 feet. Spectacular sunsets are routine here above the clouds. Due to its location, this peak is one of two premier observing sites in the Northern Hemisphere (the other being Mauna Kea in the Hawaiian Islands). The island, La Palma, is the most northeasterly of the Canary Islands, just a few hundred miles from the Moroccan coast of Africa.
The peak, called Roque de los Muchachos, is named after an outcropping of volcanic rocks looking somewhat like tall humans. It perches on the very rim of a huge caldera formed from the collapse of the Taburiente volcano a half million years ago. The caldera is six miles across and almost as deep as the Grand Canyon. From the top, at sunset one can see the shadow of the mountain cast across the Atlantic Ocean, with the island of Tenerife clearly visible.
It is here that the European Northern Observatory operates thirteen world class telescopes, with teams from Great Britain, Italy, Spain, the United States, and other countries, all working on scientific projects to explore the farthest reaches of space and time. In addition to Grantecan, other famous telescopes abound, such as the William Herschel Telescope (4.2 meters), the TNG (Galileo), and “MAGIC,” a twin set of huge 56 foot mirrors pointed horizontally and looking for particle showers caused by cosmic rays.
The University of Florida is a 5% partner in the Grantecan telescope, inaugurated in 2009, and is designing and utilizing instruments such as CanariCam for use on the facility. In return, the Florida team has access to the telescope for its own projects. Because the target is to commission CanariCam on the telescope next week at the Nasmyth focus (one of the observing spots on the telescope), the Florida team has exclusive access to the telescope for a few nights, both to commission the instrument and begin collecting important scientific data. One can detect the envy in the voices of other astronomers during mealtime discussions. “Ah, you're on the Florida team. You have the Nasmyth focus next week!”
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