
The University of New Mexico
NEWS RELEASE
June 22, 2006
UNM Astronomers Search for Precision with New Ground-based TelescopeAstronomers at the University of New Mexico are developing an exciting new telescope with capabilities that are unrivaled in astronomy circles. The CCD/Transit Instrument with Innovative Instrumentation, or CTI-II, is a special-purpose telescope where accuracy and precision are the key components allowing for unprecedented research opportunities.
The ground-based telescope does not move to survey the sky, a feature that allows for more precise measurements of brightness and position.
“The unique, stationary telescope is more precise than any other ground-based telescope because it is literally fixed to the Earth,” said John McGraw, professor, Physics and Astronomy. “It doesn't move to track the stars as do most telescopes. It operates only in a ‘transit' mode, observing in great detail a square patch of sky about the size of four full moons. The patch continuously passes overhead as the Earth rotates.
“Two hundred years ago transit telescopes were the epitome of precision measurement in science. Today, with CTI-II we are merging this centuries-old technique to modern optical systems, electronic detectors and computers to continue our quest for understanding about the wonderful array of objects in the universe, and the forces that activate them.”
Once built, the telescope, which is part of the Near Earth Space Surveillance Initiative (NESSI), will be based near the west Texas town of Ft. Davis at the McDonald Observatory where clear nighttime skies are abundant.
Most astronomical measurements of the brightness, positions and motions of objects in the sky are made with telescopes on Earth. The biggest disadvantage in using ground-based telescopes is that the Earth's atmosphere absorbs a great deal of light from astronomical objects and the images are blurred by the turbulent atmosphere.
To help alleviate this problem, UNM astronomers are utilizing electronic light detectors called charge-coupled devices or CCDs, which are used in most digital cameras. If a galaxy changes brightness by more than only a few parts in a thousand, the CTI-II will detect and record those changes.
The telescope, under computer control, uses a prototype mirror six feet in diameter that was originally designed for the Hubble Space Telescope. It has the capability of producing more than 250 gigabytes of image data containing millions of galaxies and stars measured in five colors ranging from green to somewhat redder than the eye can see in a continuous high-efficiency readout.
Numerous fundamental astronomical research programs depend upon the ability to make accurate measurements of the brightness, positions and motions of objects in the sky. If these highly precise measurements can be made daily over an interval of years, as they will for the UNM telescope, a unique record of our dynamic universe can be maintained.
“We'll be able to make precise brightness measurements every night, all night, year after year, enabling the CTI-II telescope to maintain a distinctive record of our dynamic universe that hasn't been made before,” said McGraw.
As an example of the application of precise brightness measurements, the centers of most, and conceivably all, spiral galaxies like our own Milky Way harbor supermassive black holes millions to billions of times more massive than our own sun. The hallmark of these supermassive black holes is brightness changes caused by galaxy material – stars and gas – falling into the vicinity of the black hole.
“Every clear night, the UNM telescope will monitor more than a million galaxies, making measurements of the light output of each of them,” said McGraw. “If a galaxy changes brightness by more than only a few parts in a thousand, the telescope will detect and record those changes. The record of the light from each galaxy will allow astronomers to decide whether the galaxy harbors a supermassive black hole.”
Observations of many galaxies will statistically determine if all galaxies contain black holes, whether black hole formation is a prerequisite or a consequence of the formation of galaxies, and whether the currently accepted single model of the galaxy core black holes completely explains the mechanisms at work deep in the centers of galaxies.
CTI-II also precisely measures positions, motions and distances to stars. In our own Milky Way Galaxy, faint red stars, the existence of which was discovered in only the last few years, dot our “solar neighborhood,” a region of space within a few tens of light years of our sun. Measuring the motions and distances to these stars will reveal details of the formation history of the Milky Way and may shed light on the unseen mass that seems to dominate the total mass of our Galaxy and others.
Once completed, in approximately two years, the CTI-II will provide concepts, techniques, hardware and software, and the ability to field test components of sky surveillance systems including exploration of the current ‘find and target' system and technologies and systems for inclusion in the development of the Air Force Space Surveillance Telescope (AFSST).
“Our unique telescope will produce precision data on the nearest stars and on distant galaxies,” said McGraw. “It will enable many new scientific programs in which university and high school students will be engaged and educated in science, math and engineering. At the same time, our project produces and tests new observing and computational technologies and techniques that directly apply to the mission of our Air Force Research Laboratory sponsors.”
Because it will operate for years, the lasting legacy for the future of ground-based astronomy will be the most precisely calibrated area on the sky, a useful reference for other telescopes and the observations and surveys they will accomplish.
“Every clear night for seven years, CTI-II will produce more than 250 gigabytes of digital image data,” said McGraw. “Those precision images, containing millions of stars and galaxies, will provide an unprecedented record of the brightness, color, position, motion and brightness variations of every one of those objects. CTI-II will produce so much data each night that our science team cannot extract all the useful information. To maximize the impact of CTI-II, our team will share data, literally as it is acquired, with the astronomical and educational communities.”
Due to the vast amount of data that will be produced, the technological limits of computing hardware and software will be pushed. McGraw and his team are collaborating with UNM computer scientists and engineers and their students to implement a forefront computing system that will allow astronomers and students worldwide to access our data and make their own discoveries.
During the two years it has already been under design, about 12 graduate and eight undergraduate students at UNM have been employed as research and laboratory assistants with the project. Ten professors and research faculty members are supervising their work.
“Students will play an integral role in analyzing the vast amount of CTI-II data,” McGraw added. “Our experience indicates that CTI-II data will result in at least one Ph. D. and one Master's thesis every year it operates.
“We also plan for CTI-II data to be used in primary and secondary schools. Using CTI-II data and our data system, there is no reason a high school student, collaborating with UNM astronomers, cannot make an important astronomical discovery. Data from our telescope will open “discovery space” to high school students, as well as to the astronomical community. Data from CTI-II will allow high school students as well as professional astronomers to make discoveries about the content, structure and operation of our universe.”
The development of CTI-II is part of a major collaboration between UNM and The University of Texas at Austin. When completed, the telescope will be move to UT-A's McDonald Observatory in West Texas, the continental observatory site with the darkest night skies. The collaborative project is funded by a grant from the Air Force Research Laboratory enabled by the support of U.S. Representative Henry Bonilla (R-Texas).
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