Observational Facilities

Princeton University has focused much of its observational effort on wide-field surveys of the sky, including optical imaging and spectroscopy, searches for extrasolar planets, and detailed observations of the cosmic microwave background. Undergraduate and graduate students and postdoctoral researchers are involved in all aspects of this effort. Key faculty members include Robert Lupton, Jenny Greene, Michael Strauss, and Jim Gunn on the optical surveys; Jo Dunkley, Lyman Page, Suzanne Staggs, Bill Jones, and David Spergel on the cosmic microwave background; and Gaspar Bakos, Jill Knapp, Ed Turner, Jeremy Kasdin, and Robert Vanderbei on searches for extrasolar planets.

Princeton University played a leadership role in the Sloan Digital Sky Survey (SDSS).  In the 15+ years that the survey has been in operation, over 6800 scientific papers have been written, including many by Princeton researchers. The survey has led to the discovery of the most distant quasars, precise measurements of the properties and clustering of galaxies, and determination of structure in the halo of the Milky Way.

The SDSS has been very successful at characterizing galaxies in the low-redshift universe. Doing the equivalent at distant cosmic epochs requires a substantially larger collecting area. As part of the SuMIRe (Subaru Measurements of Images and Redshifts) project, Princeton University is collaborating with the Japanese and Taiwanese astronomical communities in a wide-field imaging survey of the sky with the Subaru 8.2 meter telescope. Hyper Suprime-Cam is a 1.77 deg^2 imaging camera, and we are carrying out a 300-night 1400 deg^2 imaging survey in multiple bands to r~26 (3.5 magnitudes deeper than SDSS), as well as deeper imaging in smaller areas. These data are being used to study the evolution of galaxies, the distribution of dark matter through weak lensing, the most distant stars in our Milky Way, and the most distant quasars in the Universe. 

We are also part of an international collaboration to build a multi-object spectrograph for the Subaru Telescope, which represents the second component of the SuMIRe project. The Prime Focus Spectrograph (PFS) will have 2394 fibers deployable over 1.3 deg^2, with spectral coverage from 0.38 to 1.26 microns.  It will start a 300-night survey of its own in 2019, targeting objects from the HSC survey, to study galaxy evolution and large-scale structure at high redshifts (focused both at 0.7 < z < 2, and also at higher redshifts) and to study the kinematics and chemical composition of the outer halo of the Milky Way and M31. 

We are also playing a major role in the Large Synoptic Survey Telescope (LSST), which will carry out its 10-year survey of 20,000 deg^2 of the Southern skies starting in 2022, with a dedicated 6.7-meter telescope.  HSC is very much a precursor for LSST, and we are laying the scientific groundwork for LSST with our HSC observations.  We are leading the development of the imaging pipelines for both projects, developing state-of-the-art software for measuring the brightness, positions, and morphologies of what will eventually be tens of billions of galaxies and stars.  

The Wide-Field Infrared Space Telescope (WFIRST) will be a 2.4-meter wide-field imaging telescope which will operate in the near-infrared. Expected to launch around 2023, it will measure the large-scale distribution of galaxies and dark matter, and search for extrasolar planets via microlensing. Princeton is playing a leading role in the project: Jeremy Kasdin and David Spergel are co-chairs of the Science Working Group, and Adam Burrows, Jenny Greene, and Robert Lupton are members of WFIRST Science Investigation teams.

An imaging survey to search for planets and debris disk around other stars, the Subaru Strategic Exploration of Exoplanets and Disk Survey (SEEDS), a collaboration between Japanese and Princeton astronomers, uses adaptive optics and a coronagraph on the Subaru 8.2-meter telescope. It operated over 120 nights, and has produced several Princeton PhD theses. We are now building the successor instrument, The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), which will be able to do spatially resolved spectroscopy of protoplanetary disks to understand the process by which stars may form.  

We have played a major role in the building of the Wilkinson Microwave Anisotropy Probe (WMAP) and the analysis of its data, resulting in the three most cited refereed papers in astrophysics in the last decade. These data measuring fluctuations in the Cosmic Microwave Background have firmly established what is now the standard cosmological model, and allow a determination of the age, composition, structure, and geometry of the Universe to exquisite precision.  We are similarly leading the Atacama Cosmology Telescope (ACT) to measure the fluctuations in the CMB on smaller angular scales, which is enabling further cosmological probes and explore the physics of the interaction of CMB photons with matter in the relatively nearby universe.

Please consult the research page on planetary astrophysics to learn more about the observational facilities Princeton has developed for the study of extrasolar planets.


2.5-m telescope at Apache Point Observatory, used in the Sloan Digital Sky Survey