--> Fred Gillett's Legacy | Gemini Observatory

Change page style: 

Fred Gillett's Legacy

Figure 1

Fred Gillett

By Doug Simons

Inspired by the creative genius of the GeminiFocus editors and the International Year of Astronomy celebrations occurring around the globe, this edition features some truly remarkable and fascinating accounts of the “birth” of the giant twin telescopes we now call Gemini. Accounts are given of the singular contributions of scientists, engineers, and managers who played crucial roles in the development of Gemini. These include leaders like Sidney Wolff, who brought together the resources in Tucson to take a concept to reality, and Matt Mountain, Gemini’s director throughout the construction phase of the project. His vision and tenacity helped lead the project from the drawing board to massive chunks of steel and glass. This issue also features the mathematical genius of Brent Ellerbroek, whom the Gemini Project relied upon heavily in its early days to ground its designs in an emerging technology we now take for granted: adaptive optics. David Crampton and Roger Davies are also featured for their leadership and drive behind Gemini’s most scientifically productive instruments, the Gemini Multi-object Spectrographs at Gemini North and South.

The core Gemini engineering and management team–comprised of Dick Kurz, Larry Stepp, Keith Raybould, Jim Oschmann, and Rick McGonegal–is featured as well. I witnessed firsthand the management and engineering wizardry of these key people in the original Tucson project office as they plowed daily through a complex trade space of cost, performance, and scheduling like a snowplow on Mauna Kea this winter! (See the June 2009 issue of GeminiFocus here.) Finally, in this article, I have the privilege of sharing with you my own perspectives on Fred Gillett (pictured), the man whose image, on a memorial plaque, adorns the interior of the dome at Gemini North, watching as his “baby” harvests photons that seed tomorrow’s discoveries.

Fred was working at the National Optical Astronomy Observatory (NOAO) the first time I met him in 1994. I had just arrived on the scene in Tucson as Gemini’s new “systems scientist.” Matt Mountain, who was the project scientist at the time, hired me to help interface between Gemini’s emerging international science community and the engineering team in Tucson, where low-level design trades were being made almost daily. Though Fred was not formally on Gemini’s staff at the time, in practice he was already heavily involved in the project, providing crucial guidance on top-level performance requirements for the telescopes, instruments, and sites. At the time, I was trying to absorb a huge amount of information flowing across 10 time zones, but I pretty quickly identified a few aspects of the telescope design under consideration that I felt were either incredibly visionary or simply ludicrous. Chief among these was the emissivity specification, as stated in Gemini’s Science Requirements Document: “The fully optimized IR configuration will have a telescope emissivity, including scattering and diffraction, of 4% with a goal of 2% immediately after coating or recoating optics, with 0.5% maximum degradation during operations, at any single wavelength beyond 2.2 microns.”

Having spent my graduate career and first post-doctoral period working on infrared systems on Mauna Kea, I instantly knew how hard it was going to be to reach that goal, which was around three times smaller than what the best ground-based telescopes in the world were currently achieving. It could simply not be done without the invention of new technology. Fred knew that and accepted the challenge by becoming the driving force behind a program to develop advanced protected silver coatings for application on Gemini’s optics. He worked meticulously to test one “formula” after another, systematically zeroing in on a combination of materials that would yield not only the desired emissivity, but could also withstand the harsh conditions Gemini’s enormous mirrors would experience. Fred used an instrument dubbed the “Two Tummy Toad” (an old single-element lab infrared photometer) and no shortage of liquid nitrogen and patience to painstakingly measure the emissivity of test coatings. This work, which he quietly conducted in a lab in the basement of NOAO, would ultimately lead to the silver coatings that are now used routinely at Gemini and yield a focal plane with ~3% emissivity – the most sensitive infrared focal plane of any large aperture ground-based telescope.

Fred’s contributions go far beyond the silver coatings, however. He was the “keeper” of the most fundamental telescope performance requirements in a development environment that was occasionally hostile to his vision and, given enormous schedule and cost pressure, liable to settle for the status quo. Fred was as relentless in his pursuit of the ultimate infrared telescopes as he was mild-mannered in his approach. He almost never outwardly got mad—he simply resolved to overcome whatever predicament confronted him. Most of the time, he did just that.

Beyond emissivity, he was just as concerned about ensuring that Gemini meet its fundamental image quality specification to place at least 50% of the 2.2-micron energy gathered by the telescope into an aperture 0.1 arcsecond in diameter, allowing for only tip/tilt correction. Almost as audacious as the emissivity requirement, this single requirement had enormous design implications for Gemini, which propagated across the entire telescope system. On countless occasions it would have been easy to relax this requirement, but Fred never gave up. His passion for image quality is manifested by the spectacular images recorded every night at Gemini, each showing our trademark faint diffraction spikes and stable, smooth point-spread functions.

Finally, no account of Fred’s numerous contributions to Gemini could be complete without mentioning how he skillfully worked with Al Fowler and Mike Merrill at NOAO to develop the ALADDIN 1024 ´ 1024 InSb detectors used throughout the astronomy community’s instruments today. Gemini funded one of the first foundry runs of these detectors and I was always amazed at how Fred and Al were able to carefully marry InSb detectors of varying qualities with multiplexers, interpret test results arriving regularly from Santa Barbara and NOAO’s own lab, and produce the detectors that were eventually used in the Near-infrared Imager and Spectrometer (NIRI), the Gemini Near-infrared Spectrograph (GNIRS), the Near-infrared Coronagraphic Imager (NICI), and the PHOENIX spectrometer.

Beyond the magnitude of Fred’s vision, passion, and technical insight, the greatest lesson I learned from Fred as a young astronomer swept up in a huge telescope project was this: always let “science” be your guiding light through complex situations. In a world that is often blinded by complex political, financial, or technical arguments that can lead people in one direction or another, time and time again I watched Fred take the “high road” and unilaterally focus astronomers and engineers on a single simple path forward. I’ve witnessed heated debates behind closed doors at Gemini on countless occasions, only to be settled when Matt would turn to Fred, who had been quiet the whole time, and Fred would say in his calm no-nonsense voice, “That’s all well and good but here’s what we need to do…”

I could go on and on about Fred, but will end by simply saying that I have always been amazed by the connections between seemingly small things, like Fred’s pioneering tests of silver coatings which only a handful of people really even knew was going on, and the discoveries made at Gemini using those same coatings. Fred did not live to see his vision fully bear fruit at Gemini, but I am nonetheless certain that had he been around to see the Gemini twins we now use every night, he would have been incredibly proud (see text box below). I was blessed to have had the opportunity to work with Fred in the twilight of his career and will never forget the look in his eyes as he walked out of the Hilo Base Facility for the last time with a beautiful flower lei around his neck. At the time, we both knew it would likely be the last time he would set foot in Gemini. I knew that at Gemini, his footsteps would never be filled again.

Figure 2

Fred Gillett would have been particularly enamored by discoveries like the planetary system surrounding HR 8799 which was imaged by Gemini North last year–a telescope Fred played a central role in designing. The stunning image (see image and article starting on page 44 of the June 2009 issue of GeminiFocus) obtained by a team led by Christian Marois of the National Research Council of Canada’s Herzberg Institute for Astrophysics and members from the U.S. and U.K., is the first image of a solar system, beyond our own, since Galileo published drawings of the planets in our own solar system (see image below, left, of Jupiter and its four brightest moons) in his book Sidereus Nuncius, or The Sidereal Messenger. While hundreds of planets have been detected through indirect means in recent years, what makes direct imaging of extrasolar planets so valuable is that, through this technique, it is possible to actually map the orbits of these planets around their host star and measure their masses, luminosities, and chemical compositions. The planets discovered are between seven and ten times more massive than Jupiter and are so young (60 million years) that they radiate copious amounts of infrared radiation, helping us detect them at the 130-light-year distance to HR 8799.

Gemini Observatory Participants