European Stars and Stripes (Newspaper) - February 10, 1990, Darmstadt, Hesse                                13,796 feet above Tern level Mauna Kea r preserving the dark Hawaii has stringent _ Laws to curb Light pollution that might prevent instruments from picking up dim Light from Distant celestial objects. Municipalities homeowners and resort hotels must shield their lights. Ringside seat for viewing the heaven the Keck Telescope is joining a comp Lei of observatories atop the Mauna Kea Volcano m Hawaii perhaps the world s Best Telescope site. Clear nights. About 68 percent of nights Are perfectly Clear for at least 6 hours an additional 15 percent Are Only slightly less perfect. Calm air. Small scale turbulence caused by temperature fluctuations in the air can distort the images of celestial objects Bui the flow of air Over Mauna Kea s Summit is smooth most of me time giving very steady urn distorted images. Darkness. Mauna Kea is one of the world s darkest Sites with no Large population centers to Light the Yghi sky or log the atmosphere with Dull and aerosol particles. Dryness. Relative humidity at the Summit typically 10 percenter less. The aridity allows infrared radiation which would otherwise be absorbed by moisture in the air to reach the telescopes in Quantity. Preventing distortion the Keck Telescope has a composite Mirror consisting of 36 hexagonal segments. Each segment is partly undergirded by motor driven supports that Are adjusted twice a Sec Ond to compensate for Mirror distortions from temperature changes and other factors. Huge fans keep air in Side the Observatory dome at outside temperatures. Hexagonal Mirror f Jeff of cd o 2o m / 8o o33 stars and stripes bookstores stars and stripes bookstores saturday february 10, 1990 the stars and stripes Page 17