TUCSON, Ariz. — That 4-meter telescope at Kitt Peak National Observatory is one huge piece of equipment.
Seeing one of the world’s largest optical telescopes with observatory’s director, Lori E. Allen, as their guide, participants in this week’s Faith and Astronomy Workshop put on by the Vatican Observatory got a better understanding of how astronomers are helping unlock some of the mysteries of the universe during a visit Thursday.
The telescope has been in operation since 1970 under a 180-foot-tall dome atop Kitt Peak, located 54 miles southwest of Tucson.
Allen said the telescope is available year-round except for Christmas Eve and Christmas Day. As the 24 workshop participants marveled at the size of the monstrous telescope, astronomer Paul Canton, 29, a doctoral student at the University of Oklahoma, was preparing to use it to measure binary white dwarfs in a collaborative effort with other scientists to detect gravitational waves as predicted by Albert Einstein’s theory of general relativity.
Canton’s work is among some of the cutting edge work astronomers are undertaking these days.
The workshop participants also visited the neighboring dome housing the 90-inch Bok Telescope operated by the University of Arizona’s Steward Observatory. Three Chinese researchers were preparing for a night of observing by cooling the charge coupled device (camera) attached to the telescope with liquid nitrogen to make it more sensitive to photons from distant planetary nebulae.
Hu Zou, a staff member of the Beijing National Astronomical Observatory, said that the group had been measuring nebulae structures for 10 nights and had two more to gather data.
The telescope is the same one used by Jesuit Father Chis Corbally of the Vatican Observatory staff, who joined the workshop visitors, when he conducted star surveys over the years.
The Kitt Peak excursion was the third of the week as part of the workshop. Earlier visits included the Lunar and Planetary Lab Imagining Center and the Richard F. Caris Mirror Lab, both at the University of Arizona in Tucson.
The mirror lab, visited Wednesday, particularly impressed the participants because of the high-tech innovations being used to produce the largest telescopic mirrors in the world.
The lab’s Alan Brass said it takes nearly a year to produce an 8.4-meter diameter (nearly 28 feet) mirror in a process developed by astronomer Roger Angel. Prior to Angel’s innovation it was impossible to make a mirror so large out of a single block of glass.
Angel’s solution yields a piece of glass with a hollow, honeycomb interior. The process involves putting clear glass into a honeycomb-shaped mold in a two-and-a-half story rotating furnace. The temperature in the furnace is gradually raised to 2,100 degrees, allowing the glass to melt and fall into the mold.
The furnace spins, allowing the molten glass to flow into a parabolic shape. Computer precision grinding follows once the glass cools to produce the mirrored surface.
The lab completed its 19th mirror last year. It will be used in the Large Synoptic Survey Telescope being built in the Andes in Chile. Once online, the telescope will allow astronomers to take 1,000 pairs of exposures each evening and will cover the entire night sky in three days in the search for objects that “change and move.”
The first field trip to the imaging center Tuesday showcased several projects, including the OSIRIS-REx asteroid sample return mission set for launch in September and the digital archiving of photographs from 1960s-era spacecraft missions to the moon.
The Lunar and Planetary Lab is playing a key role in the asteroid mission, which will find the OSIRIS-REx spacecraft making a seven-year round-trip journey to Asteroid 101955 Bennu. The spacecraft will take two years to get to the asteroid, two or more years to survey it and obtain a sample and two years to return with a landing in Utah.
Dolores Hill, a meteorite expert at the lab, explained that the mission will help determine the composition of asteroids and allow for comparison to meteorites that tumbled to Earth to piece together the origins of the solar system. Scientists currently are working to determine how much material the spacecraft will be able to pick up in what amounts to a brief touch-and-go “landing” on the 1,600-foot diameter asteroid.
The archiving work is vital to preserve the photographs taken by the Survey missions to the moon that paved the way for the Apollo landings on Earth’s satellite. John Anderson, senior media technician, has archived 94,000 images since March. He’s got hundreds of thousands to go.