Time Series Center   Harvard University

The Taiwan-America Occultation Survey (TAOS) aims to determine the number of small icy bodies in the outer reach of the Solar System by means of stellar occultation. An array of 4 robotic small (D=0.5 m), wide-field (f/1.9) telescopes have been installed at Lulin Observatory in Taiwan to simultaneously monitor some thousand of stars for such rare occultation events. Because a typical occultation event by a TNO a few km across will last for only a fraction of a second, fast photometry is necessary. A special CCD readout scheme has been devised to allow for stellar photometry taken a few times per second. Effective analysis pipelines have been developed to process stellar light curves and to correlate any possible flux changes among all telescopes. A few billion photometric measurements have been collected since the routine survey began in early 2005. The preliminary result of a very low detection rate suggests a deficit of small TNOs down to a few km size, consistent with the extrapolation of some recent studies of larger (30-100 km) TNOs.

The ESSENCE supernova survey has been undertaken to measure the equation of state parameter of the dark energy. It uses 30 half nights/year on the Blanco telescope. ESSENCE survey data are taken using the MOSAIC II imaging camera, which consists of eight 2048x4096 pixel charge-coupled devices (CCDs) arranged in two rows of four, with gaps corresponding to approximately 50 pixels between rows and 35 pixels between columns. In the f/2.87 beam at prime focus, this yields a field of view of 0.6 degrees on a side for a total area of 0.36 square degrees on the sky. ESSENCE uses image differencing photometry. A side-product of the survey is stellar light curves.

The Optical Gravitational Lensing Experiment (OGLE) project is a long term project with the main goal of searching for the dark matter with microlensing phenomena. The first phase started in 1991. In the late 1991 the funds for the OGLE microlensing project were granted by the State Committee for Scientific Research to the team of astronomers from the Warsaw University Observatory. A 1.3m dedicated telescope at the Las Campanas Observatory, Chile, started operating in the second phase of the project in 1996. The third phase began in 2001. The OGLE project has also produced a huge catalog of variable stars, and light curves in general.

The MACHO project was a collaboration to search for MACHOs (objects like brown dwarfs or planets) using a camera with a two channel system that employs eight 2048*2048 CCDs on the 1.3-meter (50-inch) telescope of the Mount Stromlo observatory. It was led by Charles Alcock. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. The MACHO team found several dozen microlensing events in the Galactic Bulge and Large Magellanic Cloud. The data taken by the project has been an incredible source for finding variable stars, and for astronomical light curves in general.

Pan-STARRS will be composed of four individual optical systems, each with a 1.8 meter diameter mirror observing the same region of sky simultaneously. Each mirror will have a 3 degree field of view and be equipped with a CCD digital camera with 1.4 billion pixels. The spatial sampling of the sky will be about 0.3 arcseconds. While searching for potential killer asteroids in survey mode Pan-STARRS will cover 6,000 square degrees per night. The whole available sky as seen from Hawaii will be observed 3 times during the dark time in each lunar cycle.

PS1 is essentially one quarter of Pan-STARRS, and has been built to test many of the features of the full PS4 telescope. It has the same optics design and camera design as anticipated for the full version of Pan-STARRS. PS1 has been built on the site of the south dome of the old LURE observatory on Haleakala, Maui. First light occurred in June 2006. PS1 will be used to make a full-sky survey that will provide astrometric and photometric calibration data that will be used for the full Pan-STARRS survey.

HATNet (The Hungarian-made Automated Telescope Network) is a network of six small (11cm diameter), wide-field (8x8 deg), fully-automated "HAT" telescopes. The scientific goal of the project is to detect and characterize extrasolar planets (exoplanets; those outside the Solar System), and also to find and follow bright variable stars. The network is maintained by the Harvard-Smithsonian Center for Astrophysics. There are two main stations: the Fred Lawrence Whipple Observatory (FLWO) of the Smithsonian Astrophysical Observatory (SAO) and the Submillimeter Array (SMA) site of SAO atop Mauna Kea, Hawaii.

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