Taiwan has also developed and built two world-class telescopes atop Hawaiian volcanoes--the Sub-Millimeter Array (SMA) and the Array for Microwave Background Anisotropy (AMiBA). The SMA--the world's first astronomical radio telescope array making observations at sub-millimeter wavelengths--was jointly built by the Academia Sinica's Institute for Astronomy and Astrophysics (ASIAA) and the Smithsonian Astrophysical Observatory (SAO). Its observations focus on stars' formation and late-stage evolution. Last October, a team from ASIAA and National Taiwan University (NTU) completed the installation of AMiBA on Mauna Loa. AMiBA--the world's first single-platform array working at millimeter wavelength--is expected to begin announcing important findings by the end of this year.

Constructed at an elevation of nearly 4,000 meters, the SMA and AMiBA projects had to overcome the challenges posed by strong winds, low temperatures and the limited resources available at altitude. That they were able to do so is a testament to the originality and meticulousness of Taiwanese design and development in telescopes, and to the growing maturity of Taiwanese scientific observation and analysis. The projects have also catapulted Taiwan's astronomical researchers into the world's top ranks.

When people think of Hawaii, they generally think of hordes of tourists visiting for the sun, the sand, the surf, and the ocean sports, not to mention the beautiful and shapely women in grass skirts. But America's youngest and southernmost state is more than just a renowned tourism hotspot. In the scientific community, Hawaii is known as the most important site for astronomical research in the Northern Hemisphere.

Accompanied by ASIAA engineers, a research team from the NTU Department of Electrical Engineering climbs onto AMiBA's platform to view the equipment.

A research paradise

The Hawaiian archipelago rises in the middle of the North Pacific between Asia and North America, somewhat south of the Tropic of Cancer. It runs from northwest to southeast and includes 137 volcanic islands, the four most important and familiar of which are Oahu, Hawaii, Kauai and Maui.

Honolulu's Waikiki Beach on the island of Oahu is one of the most visited vacation spots in the world. The crowds paying as much as NT$10,000 per night to stay in one of its rows of hotels come to sunbathe on its fine white sands, splash in its waves, and shop its ubiquitous upscale boutiques.

Hawaii (the "Big Island") is the largest of the Hawaiian Islands. Though not as well known as Oahu, it is home to two 4,000-meter volcanic peaks. With a climate that typically features 300 clear days a year and peaks that rise far above interfering clouds and water vapor, the big island is an ideal place for making astronomical observations. Including Taiwan, some 13 nations currently operate telescopes and observation stations on the island.

We fly from Waikiki to Hilo, the Big Island's largest city, in the company of the NTU research team on June 10 at 8:30 a.m. The team is on Hawaii for just one week and is determined to squeeze in a trip to AMiBA.

"It's a rare opportunity," says an excited Lin Chin-shen, a PhD candidate in NTU's Graduate Institute of Communications Engineering. "Besides, we produced some of AMiBA's electronics."

In fact, AMiBA was jointly built by the Preparatory Office of ASIAA, and the Departments of Physics and Electrical Engineering at NTU. The telescope, which came online in October 2006, is currently the world's only single-platform array working at millimeter wavelengths. Taking advantage of the Sunyaev-Zel'dovich Effect, AMiBA is using observations of high red-shift galaxy clusters and cosmic background radiation to explore the primordial and early structure of the universe, and its later evolution.

"Taiwan has led the AMiBA telescope project from conception, planning, design and development all the way through to construction," says Director Paul Ho, the former Harvard professor who leads ASIAA and who headed the AMiBA project. "It's a great design, one that other countries don't have. It's an extremely internationally competitive telescope," he continues in slightly broken, Cantonese-accented Mandarin.

AMiBA is an array telescope that currently consists of seven dishes mounted on a platform. Any two of these dishes can operate in conjunction, providing 21 observational configurations. At left, part of a raw data set from an AMiBA observation of Jupiter. An image of Jupiter derived from this data--the first AMiBA has produced of a celestial object, is shown at middle. At right, an image of Jupiter taken with an optical telescope.

Six legs and seven eyes

Built at an elevation of 3,426 meters, AMiBA sits well up the slopes of the 4,169-meter Mauna Loa, the Big Island's second-tallest peak. The drive up the mountain, which stands to the southwest of Hilo, doesn't take that long, but snakes through some very rugged terrain.

The continuous thunking of volcanic stones against the undercarriage of the Ford we rented at the airport has us a little nervous, and we have to endure it for two hours before arriving at the base.

AMiBA's "body" consists of a hexagonal platform atop at hexapod mount. Instead of the giant lens of an optical telescope, seven 60-centimeter dishes are mounted atop the platform in an arrangement that makes it look like some kind of strange beast straight out of a science fiction film. Johnson Han, an ASIAA engineer stationed in Hawaii, explains that AMiBA has nine principal components, including the mount, the platform, the dish antennas, the receivers, the correlator, the local oscillator, the intermediate frequency signal processor, and the control system. "Each of the mount's six legs can be extended or retracted, allowing the dishes to be pointed at any location in the sky," says Han. "The design makes it nimble, sort of like a six-legged cephalopod."

We climb into an elevator that lifts us five meters above the ground, a vantage that allows us to look down at the telescope. Having multiple dishes, AMiBA is what is known as an array telescope. In AMiBA's case, any two of these dishes can be made to operate in conjunction, allowing for 21 observational configurations. To ensure that no signal from the depths of space passes undetected, this seven-eyed, six-legged monster has a tremendous range of travel--an azimuth of 360°, a polarization of plus or minus 30° and an elevation down to 30° from the horizontal.

AMiBA, the world's first single-platform array working at millimeter wavelengths, makes observations of the cosmic microwave background radiation. Taiwanese scientists have led the entire project, from inception through planning and development to construction.

Probing the universe's history

AMiBA has the added advantage of allowing efficient searching of the sky. According to Dr. Chen Ming-tang, AMiBA project manager, ASIAA research fellow and deputy director of the Hilo operation, AMiBA can sample areas of up to two arc-minutes in size, or about one-fifteenth of the apparent diameter of the moon. This enables it to make observations and search for the data scientists need in a very efficient manner.

"We are going to expand our current array of seven 60-centimeter dishes to 13 120-centimeter dishes by the end of the year," says Chen. "We ultimately hope to grow it to 19 dishes."

Lin Chin-shen smiles after seeing AMiBA up and running, saying that most of the local-oscillator and amplifier chips that NTU's Department of Electrical Engineering has previously designed have gone into things like traditional electronic devices and wireless network receivers. "It never occurred to me that they could be fully integrated into an astronomical telescope," he says.

Dr. Tsai Zuo-min, a post-doctoral researcher with NTU's Graduate Institute of Communications Engineering, says that AMiBA stacks up well against Hawaii's other internationally designed and manufactured telescopes. "I never thought the circuits I'd designed would be used to look at the stars. That's just too cool!" says Tsai. "If I have a chance in the future, I'd like do cross-disciplinary work in astronomy."

Cosmology, which deals with the origins of the universe, is one of astronomy's hottest sub-disciplines. By measuring cosmic microwave background radiation (CMB), AMiBA is helping unravel the questions about the universe's origins that have so long puzzled humankind.

As Proty Jiun-huei Wu, AMiBA scientist and an associate professor with NTU's Physics Department, explains, the Big Bang brought the universe in which we live into being nearly 14 billion years ago. Radiation from that event began to propagate freely about 400,000 years later, spreading to every corner of the universe. Cosmic microwave background radiation is the term for this ancient radiation.

The universe has been expanding ever since the Big Bang, gradually stretching the wavelength of the CMB to an average of a couple millimeters, or several thousand times longer than the visible radiation emitted by the typical star. "CMB is an important piece of evidence for the Big Bang Theory," says Wu. "It allows astronomers to make observations of the early universe. This radiation has, in effect, witnessed the major events in the universe over the last 14 billion years, and contains important data on the evolution of the universe."

A sign hanging high in the AMiBA base station declares that the telescope was built by ASIAA and the NTU Department of Physics. AMiBA is also known as the Lee Yuan-tseh Array Telescope in honor of former Academia Sinica president Lee Yuan-tseh, who initiated the project.

A fly in a dark room

CMB can also be used to make observations on galactic clusters. Cosmologists believe that the CMB we observe was emitted about 14 billion years ago at a temperature of about 3,000°C. However, with the expansion of the universe since that time, it has cooled to only about -270°C. When telescopes like AMiBA measure the CMB, galaxy clusters appear as anomalies in the temperature or other data. This makes CMB observations an ideal means for exploring known clusters and discovering new ones.

Wu says these distant galaxy clusters are like houseflies flitting through a dark room--they're incredibly hard to see. But if the wall behind the flies were to emit light, their silhouettes would be revealed. "The CMB acts as this kind of backlight to galaxy clusters," he explains.

Though AMiBA has been in operation for less than a year, it has already begun to bear fruit. On April 18, AMiBA observed interactions between the Abell 2152 cluster and the CMB using the Sunyaev-Zel'dovich Effect (SZ effect). These are the first cosmological observations Taiwanese researchers have ever gotten on their own and are expected to be published by the end of the year.

Wu explains that when the CMB and a galactic cluster exist together, some CMB photons are energized by their interaction with intracluster free electrons. This increases the frequency and temperature of these photons, while reducing the number of lower-frequency photons. In the field of cosmology, this shift is referred to as the SZ effect.

"The CMB is strongest in the 30-400 gigahertz range," says Wu. "AMiBA makes its observations at around 90 GHz, or at a wavelength of about 3 millimeters. It is currently the only telescope in the world operating and achieving results at this frequency."

AMiBA, the world's first single-platform array working at millimeter wavelengths, makes observations of the cosmic microwave background radiation. Taiwanese scientists have led the entire project, from inception through planning and development to construction.

SMA: watching stars form

Taiwan's other project, the Sub-Millimeter Array (SMA), actually predates AMiBA. Completed in 2003 by ASIAA and the Smithsonian Astrophysical Observatory, the SMA makes observations on stars' formation and their late-stage evolution, as well as on the evolution of galaxy clusters, from its 4,205-meter-high perch on Hawaii's Mauna Kea. Over the last several years, researchers have used data from the SMA to publish some 80 articles in international journals, 54 of which were written by Taiwanese scientists.

The SMA array consists of eight six-meter dishes, two of which were built in Taiwan. By using all eight together, extremely high resolutions can be achieved. In fact, in such circumstances it can emulate a 500-meter dish.

"Even though we poured money and manpower into the SMA, we still had to get the most crucial manufacturing technologies via a technology transfer from the US," says Chen Ming-tang. "Simply put, we duplicated someone else's technology for the SMA. The AMiBA project, on the other hand, was Taiwan-led. And it was a much more complex project."

Taiwan began working on the AMiBA project, which has been funded by some NT$300 million in grants from organizations including the Ministry of Education and the National Science Council, in 1999. It was originally slated to come online in 2004, but the development team's lack of array-building experience coupled with the difficulties they encountered in manufacturing its precision electronics and machinery delayed AMiBA's completion for two years.

"AMiBA is composed of numerous precision electronic modules and other small parts," explains Chen. "Even the slightest defect in one of these can make it inoperable. Then there's the harsh environment at that altitude--you have powerful winds that get into everything and day-night temperature differentials can be as much as 20°C or more. Guaranteeing that your electronics will operate without fail in such an adverse climate is a real challenge."

AMiBA is an array telescope that currently consists of seven dishes mounted on a platform. Any two of these dishes can operate in conjunction, providing 21 observational configurations. At left, part of a raw data set from an AMiBA observation of Jupiter. An image of Jupiter derived from this data--the first AMiBA has produced of a celestial object, is shown at middle. At right, an image of Jupiter taken with an optical telescope.

A new star on Mauna Loa

The location on Mauna Loa was another source of headaches for the team. Mauna Loa, Hawaiian for "long mountain," rises up from the bed of the Pacific Ocean. It is the world's largest shield volcano and has erupted as recently as 1984.

The majority of Hawaii's telescopes are on Mauna Kea rather than Mauna Loa because Mauna Loa is still active and therefore dangerous. However, with all of Mauna Kea's available sites in use and the Hawaiian government unwilling to open up more, AMiBA ended up on Mauna Loa.

"The AMiBA site on Mauna Loa was originally just desolate," says engineer Johnson Han, his memories of the construction difficulties they faced still fresh. "There was an observation post belonging to the US's National Oceanic and Atmospheric Administration (NOAA), but there were no other telescopes. The road up here wasn't even paved; it was just surfaced with lava stones. And we had to do everything ourselves--level the ground, connect the water and electricity, move the equipment, and build the control building and workroom, as well as install and test all the precision equipment."

Their six years of hard work have paid off. AMiBA is now the largest telescope on Mauna Loa and a destination for astronomers from around the world. Han, who often brings visiting scholars up the mountain, quips that he's "just about become a professional tour guide."

With the construction of the SMA and AMiBA under its belt, ASIAA was invited to participate in the world's largest astronomical research project--the Atacama Large Millimeter/Submillimeter Array (ALMA). Nearly 20 nations are taking part in the project on Chile's Atacama Plateau. Slated to come online in 2012 at a cost of about US$1 billion, ALMA will be able to emulate a dish greater than ten kilometers in diameter.

"The competition is intense in astronomical research," says ASIAA's Paul Ho. "If Taiwan were doing it badly, we wouldn't have so many nations wanting to work with us."

AMiBA is an array telescope that currently consists of seven dishes mounted on a platform. Any two of these dishes can operate in conjunction, providing 21 observational configurations. At left, part of a raw data set from an AMiBA observation of Jupiter. An image of Jupiter derived from this data--the first AMiBA has produced of a celestial object, is shown at middle. At right, an image of Jupiter taken with an optical telescope.

Raising Taiwan'sprofile

Participating in international astronomical research and building our own world-class telescope have helped raise Taiwan's international profile and created additional opportunities for cooperation. "Dozens of scientific papers have already been published using observations from the SMA," says Ho. "Each of these papers contains a note to the effect that the SMA was jointly built by the Smithsonian Astrophysical Observatory and Taiwan's ASIAA." Ho laughs and continues, "That's great propaganda for Taiwan!"

The Republic of China flag flies alongside those of 12 other nations at another international astronomical research center on Mauna Kea. This flag is a testament to the years of hard work our scientists have put in abroad. With Taiwan's international standing forever under attack from China and our diplomatic efforts severely constrained, we can't help but be stirred by the sight of our flag flying over this kind of international venture and wish to applaud the scientists making Taiwan better known to the world.

Starlight and ancient light

You can think of the universe as containing two types of "light." The first is created by the high-energy nuclear fusion reactions that take place in stars and stellar systems. This type of "light," which covers a broad range of wavelengths, includes radio waves, infrared radiation, visible light (which has a wavelength of 400-700 nanometers), X-rays, and gamma rays. From the standpoint of the cosmos, this "light" is the "younger" of the two varieties.

The second type is more ancient. It came into being about 14 billion years ago, shortly after the Big Bang, and is known as the cosmic microwave background (CMB). As the universe has expanded, the wavelength of this ancient light has grown with it. It currently stands at several millimeters and is invisible to the naked eye. In fact, we can only observe it with specially built radio telescopes based either on the Earth or in space.

Types of astronomical telescope

Type of telescopeSpectrum monitoredWavelengthPrincipal observation targetsHigh energyX-ray, gamma-rayBlack holes, neutron stars, high-temperature matterOpticalUltraviolet, visible, and infrared light10 nm ~ 1000 μmStars, supernovas, young stars, interstellar mediumRadioMillimeter and sub-millimeter, microwave, radio100 μm ~ 20 m11Young stars, molecular clouds, interstellar medium, cosmic microwave background, atomic hydrogen emission line, nonthermal radiation

The ROC flag hangs together with those of 12 other nations just inside the entrance to the astronomical research offices on the slopes of Mauna Kea, where the SMA is located. The flag's presence is an affirmation of Taiwan's status in international astronomical circles.

Two of the Big Island's volcanoes--Mauna Loa and Kilauea in the southeast--are active. The photo shows the terrain formed after lava has cooled.

On 18 April 2007, AMiBA observed the SZ effect produced by the interaction of the A2142 galaxy cluster with the cosmic microwave background. The observations are expected to be published by the end of the year.