W.A. Hiltner and the Beginnings of Modern Astronomy in Chile

This post began with a sentence that astronomer Stephen "Shec" Shectman wrote in an email to me about the role my father, W. Albert Hiltner, played in the trajectory of astronomy in the 20th century. 

"Al of course installed the first telescope on Cerro Tololo, while the administrative structure of the observatory was still being set up."

Shec's email got me wondering. How special was that first telescope? Cerro Tololo is a mountain in northern Chile, 8000 feet up in the Atacama Desert--an extremely dry stretch of the Andes where half of the world's land-based astronomical research is now conducted, with more giant telescopes under construction. Where did Cerro Tololo and that modest telescope sit in the history of astronomy? Was it the first modern telescope in Chile? In South America? In the southern hemisphere?

My brother Bill had recently sent me an old family photo of that very telescope. On one of his trips to the mountain in the 1960s, my father was evidently so excited to start observing that he got the 0.9 meter telescope up and running before a dome had been built to house it. There were no worries about rain in the desert during the dry season. 

In the mid-1960s, my father took our family along on a couple of his trips to Tololo, where telescopes were just beginning to sprout. 

Seeking to understand that telescope's place in history, I researched telescopes in the southern hemisphere. Many had been built in the north, but the southern skies had gone relatively unstudied. Northern telescopes could not see the center of the galaxy, the Magellanic Clouds, nor countless other celestial objects visible only from the southern hemisphere. One notable telescope in the south was a 36" telescope built in 1903 on San Cristóbal Hill in the middle of Santiago, Chile, by the University of California's Lick Observatory. This telescope would of course have become less and less useful as Santiago grew and light pollution increased. South Africa drew some interest from European and American universities as a site for telescopes, culminating in the construction of the Radcliffe Telescope in 1948. At 74", it was the largest telescope in the Southern Hemisphere at the time. 

During this same stretch, in the first half of the 20th century, many observatories were being built in the north. After founding Yerkes Observatory in 1897, with the world's largest refracting telescope, the great visionary George Hale moved to Caltech in California to build a 100" reflector on Mount Wilson, and the 200" at Mount Palomar. Yerkes looked to western Texas for darker skies and a larger telescope. My father would take us along on his trips to Texas to use the 80" at McDonald Observatory. 

The sleepy pace of astronomy in the southern hemisphere ended in 1958. The story begins, surprisingly, at Yerkes Observatory, on the outskirts of a little town called Williams Bay in southeastern Wisconsin, where I grew up. For the first half of the 20th century, rural Wisconsin offered an adequate escape from urban light pollution, and enough dark, clear, photometric nights to advance knowledge. Even in the 1960s, most of the University of Chicago's astronomy faculty lived at Yerkes, widely regarded as "the birthplace of astrophysics." 

My father would serve as director of Yerkes for a stretch in the 1960s, but in 1958, a prominent astronomer by the name of Gerard Kuiper was director. That was the year Yerkes also served as birthplace for what would prove to be a great blossoming of astronomy along that extraordinary stretch of desert extending north from Chile into Peru. Astronomer Frank Edmondson tells the story in his book about the evolution of AURA--a fortuitous acronym for the Association of Universities for Research in Astronomy. Throughout my father's career, from the 1940s through the 1980s, he participated in an ongoing search for drier, darker corners of the planet to collect light from the universe. His interest shifted from rural Wisconsin to drier parts of the country--McDonald Observatory in Texas, and Kitt Peak outside Tucson, AZ--with the desert of northern Chile beckoning as a final frontier for land-based astronomy. 

In May of 1958, a Chilean astronomer named Federico Rutllant traveled to the U.S. "seeking help to build up astronomy in Chile."  His timing was auspicious. The Russian's launch of Sputnick in 1957 had sent shockwaves through America, focusing new interest on the heavens above and greatly expanding government funding of research. Yet Rutillant aroused little interest during his visits to west coast observatories. Only when he came to Yerkes and met with Gerard Kuiper and my father did he get the response he sought.

According to my father, "The three of us, that is Kuiper and Rutllant and myself, were sitting in Kuiper's office. And Rutllant at that time, at least it was my impression, was very discouraged about getting any cooperation from American institutions to build an observatory in Chile. And I can so well recall in our discussion my remarking to Kuiper, 'Well, how about Chicago trying it?" 

It turned out that the University of Chicago was not in a position to fund it, nor was AURA, which had just formed the year before. Fortunately, just days before Rutllant's visit to Yerkes, my father's proposal for a research project entitled "Galactic Field Studies" had been submitted to the Air Force. That proposal was ultimately adapted by the Air Force to fund an astronomical research station in Chile. 

Now, it's one thing to find interest and secure funding, but another altogether to figure out where to site an observatory. The Atacama Desert offers many mountains to choose from. An astronomer named Jurgen Stock was sent by AURA to test the skies above and sources of all important water below. Among the many factors, a mountain must be low enough to be accessible in winter, but high enough to stand above the fog that reaches inland from the coast each night. 7-8,000 feet proved ideal.

According to a timeline of AURA, in August 1961 a 0.41-m telescope was hauled on mule back up the 8000 foot mountain, Cerro Tololo, to test the site. An article by Hilmar Duerbeck, National and International Astronomical Activities in Chile 1842-2002, says the mountain was officially chosen for the Cerro Tololo Inter-American Observatory in 1962, and the first small telescopes went into operation in 1965.

My father took the family along on a couple of his many trips. We would stay in a house called Casa Tres on a hill overlooking La Serena, the coastal town where the observatory had its headquarters, and sometimes head up to the mountain. It was a two hour trip on dirt roads with steep, breathtaking, nerve-racking dropoffs as we wound our way 8000 feet up the mountain. My brother and I would hold Kleenex over our noses in an attempt to filter out the dust seeping up through the floorboards of the van. If it was night, jack rabbits with outsized ears would scamper off the road ahead of us. A southern hemisphere's version of a saguaro cactus stood like a sentinel at the final turn before we reached the top.

My older brother Bill remembers the evolution of the observatory this way: "Dad had been making trips there for some time. I don't know the sequence of events, but at some point a road was cut (I recall Dad talking about how big the bulldozer was) and the top of the mountain was blown off and leveled. When we were there in 1966 there were already several small telescopes installed. If I remember, two 16", a 36" (probably the one in the photo), and a Schmidt camera. All were under domes. They were probably relocated from U.S. observatories, and used for final site evaluation."

That conflicts with the account in Frank Edmonson's book, which has the 36" being installed a year later:

"During Hiltner's third period as Acting Director, January-May 1967, he had the 36" telescope mounted in the open on a concrete pad in order to carry out observations while the dome was being installed. There was little risk in doing this because it never rained at this time of year."

That year my father also hired Puerto Rican astronomer Victor Blanco as the second director of the Cerro Tololo Inter-American Observatory, ushering in 14 years of capable leadership. Blanco oversaw installation of a 4 meter telescope that would become the most productive telescope in the southern hemisphere during that era. The telescope, sister to the 4 meter on Kitt Peak in Arizona, was later named in Victor Blanco's honor.

AURA's success in establishing the first observatory in the Atacama Desert in Chile drew the interest of European nations that had previously focused their interest on South Africa. Both the climate and the political climate in South Africa were problematic, however, and in 1963, a mountain north of Tololo called La Silla was chosen for the European Southern Observatory (ESO). 

Carnegie, which had been unreceptive in 1958, also realized it needed to invest in an observatory in the desert of northern Chile to stay competitive. During our visits to Cerro Tololo in the mid-1960s, we'd sometimes drive to the next mountain over, Cerro Morado, where an astronomer named John Irwin (tall man on the left in the photo) was living with his wife. Only now, researching the story sixty years later, do I realize his job there was to find a suitable mountain for Carnegie's observatory. In 1966, he found the right mountain, named Las Campanas for the bell-like sound some of the rocks make when struck.

My research left some questions. Was that 0.9 meter telescope my father got up and running, reportedly in March of 1967, a first in some way for astronomy in the Chilean desert? ESO's timeline says their 1 meter telescope on La Silla "witnessed first light" in November of 1966, but that seems a stretch if the road to the mountain had only been completed earlier in the same year. 

Another interesting tidbit is a story of La Silla stating that Gerard Kuiper made the "first explorations of the Andes" in March of 1959. Might my father have been part of that initial expedition? 

Other great observatories have since been built in northern Chile, named for the mountains they were built upon. John Irwin participated in initial site selection for Cerro Pachon, close to Tololo and home of the Vera Rubin telescope. In the 1980s, my father was project manager for the Magellan Telescopes on Las Campanas. ESO built another observatory eight hours north at Paranal.

Astronomical facilities in northern Chile continue to grow, taking on massive dimensions. The Vera Rubin telescope is 8.4 meters across. The Giant Magellan Telescope on Las Campanas will combine seven mirrors, each 8.4 meters across. And the Extremely Large Telescope being built by ESO will have a combined diameter of 39 meters.

And it all began with a fortuitous meeting at Yerkes Observatory in 1958 of Chilean astronomer Federico Rutllant, Gerard Kuiper, and my father, W.A. Hiltner.

Fun fact: In the 1980s, the famed educator Neil deGrasse Tyson would do research for his dissertation on the 0.9 meter telescope at Tololo.