Gemini Observatory Press Releases


Peter Michaud
International Gemini Observatory
Phone: 808/974-2510, 808/987-5876 (Cell)

FOR RELEASE: June 4, 2002


High-Tech Horse Sense

En Español - Versión adaptada en Chile

Optical technicians dressed in clean suits and protective gear incorporate a little old-fashioned "horse sense" into their procedures as they use common horse soap to clean the 8-meter (26-foot) mirror of Gemini North Telescope high atop the nearly 14,000-foot (approximately 4,000 meters) peak of Mauna Kea on the Big Island of Hawai'i. The periodic cleaning is a highly complicated process involving more than 500 steps and a crew of more than 20 engineers, technicians and support personnel. The procedure includes dismounting the 24-ton mirror from the telescope structure, lowering it five stories to the basement, mounting it on a washing frame and then washing the aluminum-coated, 20cm (8-inch) thick glass mirror to remove accumulated contaminants on the mirror surface.

Once the high-tech preparation is completed, however, the Gemini team relies on some very "low-tech" expertise to actually wash the mirror surface. Through experimentation with various detergents, technicians have found that the most efficient way to clean it is to mop the mirror surface using natural sponges soaked in a detergent popularly marketed as horse shampoo, which they purchase at a general store in Hilo, Hawai'i. Optics Technician Clayton Ah Hee, who supervised the actual washing, said the soap is used because it is a strong detergent, yet is not abrasive to the multi-million dollar mirror's delicate surface, and leaves no residue. "We've found the combination of the natural sponges and horse soap to be the most efficient way to get the mirror surface completely clean," said Ah Hee. "I know this sounds kind of simple, but sometimes the simplest solutions are best, even with something as leading-edge as the Gemini telescopes. And the horse soap really works."

The use of sponges to clean the surface was originally developed by technicians at the Gemini South telescope. Technicians and engineers from Gemini South in Chile also participated in the cleaning of the Gemini North telescope, shown here.

"Eye" Wash - Gemini Observatory technicians wash the Gemini North 8.1 meter mirror while the mirror lifter (at top), stands poised to lift the 24-ton mirror back up to the telescope five-stories above.

Credit: "Kirk Pu'uohau-Pummill/Gemini Observatory"

High-Tech "Gardening" - Gemini Observatory technicians use watering cans to rinse the Gemini North 8.1 meter mirror.

Credit: "Kirk Pu'uohau-Pummill/Gemini Observatory"

Mopping Up - Gemini Observatory technicians wash the Gemini North 8.1 meter mirrorusing natural sponges and horse soap.

Credit: "Kirk Pu'uohau-Pummill/Gemini Observatory"

The Gemini Observatory is an international collaboration that has built two identical 8-meter telescopes. The telescopes are located at Mauna Kea, Hawai'i (Gemini North) and Cerro Pachón in central Chile (Gemini South), and hence provide full coverage of both hemispheres of the sky. Both telescopes incorporate new technologies that allow large, relatively thin mirrors under active control to collect and focus both optical and infrared radiation from space.

The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that allocate observing time in proportion to each country's contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the UK Particle Physics and Astronomy Research Council (PPARC), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and the Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). The Observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

Peter Michaud / / June 7, 2002