by Wayne Rosing, LCOGT Founder and Chief Technologist
I founded and incorporated Las Cumbres Global Telescope Network in 1992, but the notion of a global ring of telescopes, connected with the internet and using CCD detectors, first occurred to me in 1983. Others were discussing similar ideas. The plan was to build a global telescope (singular) dedicated to time domain astronomy. With six observing sites spread around the world, such an instrument could observe any single target continuously over many days,and could also interrupt planned operations to take data on new interesting transient objects, no matter where they might appear in the night sky.
My old world atlas has circles dating back as far as 1984, marking roughly where the LCOGT telescopes are located today. The aim was to have uniform sky coverage, pole to pole. That implied placing telescopes at roughly plus and minus thirty degrees latitude. In the South, the placement of continents pretty much determined the longitude choices. In the North, the objective was to be four hours East or West of each of the Southern sites. Then the result would be that for some periods of the year, provided the weather is clear, three sites would simultaneously be in the dark and able to image astronomical targets in the equatorial plane.
From the beginning of the project a key element was the notion of a near real-time scheduling process that would optimize the system’s choice of targets to achieve the best possible science at any given time while taking into account local conditions at the sites and scientific constraints. An additional requirement was that the entire system had to be robotic, not requiring human night assistants or remote real-time observers.
In 2005 LCOGT set about implementing this vision. By the end of 2005, LCOGT had acquired the two 2-meter Faulkes Telescopes (the FTs), located in Haleakala on Maui, Hawaii, and at Siding Spring, Australia. Although these are larger than the 1-meter telescopes that form the bulk of the current network, they add the capability of doing daily followup of fainter objects from both the Northern and Southern hemispheres.
During the next two years the foundation was developed for the global network we have today; Efforts were concentrated on upgrading the FTs, developing a software system to tie the network together, and on engineering two rings of telescopes, one on each hemisphere. LCOGT has since deployed nine 1-meter telescopes at four sites (in Chile, South Africa, Australia, and Texas), and plans to add another pair of telescopes in Tibet early in 2017. We still have the possibility of deploying three more 1-meter facilities if funding permits. In addition, seven 0.4-meter telescopes have been deployed at four sites (including the Canary Islands).
A side effect of this distributed and redundant capability is that, each year, LCOGT has tens of thousands of hours of observing time on its instrument. LCOGT scientists and partners can plan long-term key projects which may require telescope-years of observing time. There are three basic types of measurements LCOGT telescopes acquire: First, images of small patches of the sky. From these images one can derive celestial coordinates, relative brightness, and sometimes the rate of motion for stars, asteroids, near-earth objects, satellites and galaxies. Second, by taking images in multiple color bands astronomers can do photometric data reductions to classify each object based on general color characteristics. For example, blue stars are hotter than red ones. Third, spectroscopic measurements spread incoming starlight out into detailed color bins — from about 1000 colors over the visual spectrum to as many as 50000 resolved colors. Emission and absorption by specific atomic elements can be measured; chemical element abundances, stellar temperature and even local gravity can then be determined.
Current key projects on the network include:
1) The Next Generation Sample of Supernovae (PI: Andy Howell) – Using photometric and spectroscopic observations of both Type Ia and core collapse supernovae we can learn about their characteristics in a statistically significant sample. These types of exploding stars are used as astronomical ‘standard candles’, a way of measuring the distance to the far edge of the visible Universe.
2) Exploring Cool Planets beyond the Snowline (PI: Rachel Street) – Follow-up observations of microlensing events are employed to detect and study planets in the outer parts of planetary systems around distant stars. This project relies on the Einstein deflection of light by the gravity of one star to magnify, or ‘lens’, a star-planet combination found near the center of our galaxy 20,000 light years away.
3) Echo Mapping of AGN Accretion Flows (PI: Keith Horne) – By monitoring photometrically and spectroscopically a diverse sample of active galactic nuclei we can determine their physical characteristics using the reverberation mapping technique. Basically as matter falls into a large central black hole, energy is emitted and then is reflected in outer areas of the galaxy. Reconstruction of this data can give insight into the structure of galaxies.
As the first science projects matured, we complemented our imaging capabilities with low-resolution high-throughput spectrometers for the two FTs. Thanks to an NSF grant we are also building a network of high-resolution spectrometers which will be deployed as a global ring, each instrument being coupled to a pair of 1-meter telescopes. This capability will be used to validate and characterize new extrasolar planets found by space- and ground-based survey telescopes, and to advance astrophysics by studying pulsations, rotation, and the magnetic activity of stars.
It has been a decade-long effort to build LCOGT into what it is today. The vast majority of the funding to do so has come from private sources. We are grateful for support for various parts of the effort from the University of St. Andrews on behalf of Scottish Universities Physics Alliance (SUPA), the National Science Foundation, NASA, the Qatar National Research Fund (QNRF) on behalf of Qatar Environment and Energy Research Institute, and the Dill Faulkes Educational Trust. Our site partners are the Australian National University, the Cerro Tololo Inter-American Observatory (CTIO), the Institute for Astronomy in Hawaii (IfA), the Instituto de Astrofisica de Canarias (IAC), the University of Texas at Austin McDonald Observatory, the Ali Astronomical Observatory of the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), and the South African Astronomical Observatory (SAAO).
We are grateful too for the dedicated effort provided by over 150 individuals who have built LCOGT from a dream into a scientific institution of which we can all be proud.
Wayne Rosing, January 2016.
About the author. Rosing was an engineering manager at Digital Equipment Corporation (DEC) and Data General in the 1970s. He became a director of engineering at Apple Computer in 1980. There he led the Apple Lisa project, the forerunner to the Macintosh. He then went on to work at Sun Microsystems in 1985. After managing hardware development for products such as the SPARCstation, he became manager of Sun Microsystems Laboratories in 1990. From 1992 through 1996 he headed the spin-off First Person, which developed the Java Platform. He was then chief technology officer at Caere Corporation, which developed the optical character recognition product OmniPage.
Rosing served as vice president of engineering at Google from January 2001 to May 2005. In May 2005 he was appointed a senior fellow in mathematical and physical sciences at the University of California, Davis, and continued to serve as an advisor to Google.
As a hobby throughout his career, Rosing built telescopes, telescope control systems, and ground telescope mirrors. At Davis, Rosing consulted on the Large Synoptic Survey Telescope project.