Instruments

Instrumentation at the CSO (brochure)

The CSO consists of a 10.4 m diameter Leighton telescope housed in a compact dome at 4070 m altitude near the summit of Mauna Kea, Hawaii. Instruments mounted at the Cassegrain and Nasmyth foci support spectroscopy and continuum imaging at wavelengths between 2 mm and 350 μm. Observations are carried out at night. The median zenith precipitable water vapor (PWV) is about 2 mm and short wavelength (350 μm) observations are possible when the PWV falls below 1 mm, about 25% of the time. The telescope's active surface adjustment system improves the surface accuracy to about 13 μm rms. Pointing is about 3″ rms. Observatory computers support both telescope operation and immediate data reduction. Although the CSO staff will provide orientation and limited training, inexperienced observers are encouraged to collaborate with instrument teams or experienced observers. Remote observing is supported with selected instruments.

• Cameras
  • MUSIC
    The Multiwavelength Submillimeter Inductance Camera is the follow-on to Bolocam at the Cassegrain focus. In its present configuration, MUSIC has an 11×11 arcmin field of view, three simultaneous wavelengths (1.1 mm , 1.4 mm, and 2.1 mm), and 250-300 operational detectors. MUSIC is currently available for science observations although instrument upgrades continue. Measured sensitivities are 15-30 mJy beam^-1 hr^0.5 for small sources, depending on wavelength. MUSIC is available with Lissajous and raster scanning. Data reduction software, based on the existing public Bolocam analysis pipeline, continues to evolve as the instrument is better understood. MUSIC is an ideal instrument for surveying for dusty, star-forming galaxies and for star-forming regions in our own Galaxy and, with its unique, extended wavelength coverage, for studying galaxy clusters with the Sunyaev-Zeldovich effect. The MUSIC instrument team plans surveys covering many square degrees and roughly 200 galaxy clusters and welcomes inquiries about collaboration on these surveys. Remote observing with MUSIC is supported. (operational)
  • SHARC II
    The Submillimeter High Angular Resolution Camera II is a second-generation 350/450 μm CSO camera with a 12×32 bolometer array that takes full advantage of the CSO at the shortest wavelengths. In good weather, its sensitivity over a 2.5×0.9 arcmin field of view is about 1 Jy beam^-1 s^0.5, close to background-limited performance. SHARC II has been used for high-resolution imaging of debris disks, Galactic star formation, and the Galactic Center; for resolved imaging of local galaxies; and for measuring the spectral energy distributions of galaxies at redshifts up to 6. SHARC II uses liquid helium economically and has been best used in a weather-flexed mode with a lower-frequency instrument. Remote observing with SHARC II is supported. (operational)
  • SHARP
    The SHARC II Polarimeter adds the capability for submillimeter continuum polarimetry at 350 µm. SHARP operates at the 9″ telescope diffraction limit, allowing resolved images of protostellar envelopes and determination of magnetic field strengths and geometries in molecular clouds. Remote observing with SHARP is supported. (operational)
  • MAKO
    Submillimeter detector technology continues to progress. A new 350 μm camera, with ≈500 kinetic inductance detectors, is under development at Caltech and JPL. Continuing the CSO tradition of hosting state-of-the-art technology and more powerful instruments, this new camera was demonstrated astronomically in 2013 as a step toward 100,000 pixel cameras for CCAT. (experimental)
  • Bolocam
    Bolocam is the CSO’s previous millimeter-wave camera, with ≈115 functional detectors in an 8′ field of view and an instantaneous sensitivity at 1.1 mm of 100–200 mJy s^0.5 depending on weather and aggressiveness of filtering. Bolocam is mounted at the Cassegrain focus and is available in raster scan and Lissajous observing modes. An existing public analysis pipeline is available for data reduction. Bolocam has been used for photometry and surveys of dusty, star-forming galaxies and star-forming regions in our own Galaxy (including the Bolocam Galactic Plane Survey). Bolocam is being superseded by MUSIC. (retired)

• Heterodyne Systems
  A full complement of heterodyne receivers covers the atmospheric windows from 177 to 920 GHz. New 230 GHz and 460 GHz receivers have 4 GHz IF bandwidths and fully automated (synthesized) local oscillator tuning. Their balanced design, tunerless mixers provide excellent sensitivity and superb instrumental stability. Older receivers for the 345 GHz, 650 GHz, and 850 GHz atmospheric windows have 1 GHz IF bandwidths and require manual tuning. In addition, a wide band (4 GHz), manually tuned 345 GHz receiver is available for special projects. Two FFTS spectrometers are available. The high-resolution FFTS1 provides 8192 channels across a selectable bandwidth of either 1 GHz or 500 MHz that is tunable across the 4 GHz IF band. The wide-band FFTS2 provides 16384 channels across the full 4 GHz IF band. Remote observing is supported with the 230 GHz and 460 GHz receivers. (operational)

• Spectrometers
  • Z-Spec
    Z-Spec is a broadband grating spectrometer that covers the full 190–310 GHz atmospheric window instantaneously. Z-Spec is designed to measure redshifts of distant galaxies using the CO rotational ladder—at least two ¹²CO lines are redshifted into the Z-Spec bandpass for galaxies at z > 0.9. The broadband capability also allows fast line surveys of local galaxies to measure HCN, CN, CS, SO, and other molecular species. Remote observing with Z-spec is supported.
  • Zeus-2
    ZEUS-2 is a long slit echelle grating spectrometer that delivers large bandwidth (Δλ/λ up to 5%) spectra in the 350 µm, 450 μm, and 650 µm telluric windows with a resolving power R ~ 1000. Spectra can be obtained simultaneously in the different windows and the long slit provides 9 spatial pixels. The array layout and order of the echelle grating are such that the instrument can simultaneously observe—and map—the (arguably) four most important diagnostic lines in the submillimeter windows—CO (7–6), ¹³CO (6–5), and [CI] 370 µm and 609 μm—in nearby extended sources. Furthermore, over much of the redshift 1–2 interval the [CII] 158 µm and [NII] 205 µm lines can be observed simultaneously from dusty star forming galaxies, thereby characterizing both the diffuse ionized and PDR gas. ZEUS-2 is expected to be available at the CSO in 2015. (visiting)

• Other
  • Dish Surface Optimization System (Active Surface)
  • FTS/shearing interferometer (limited availability)
  • Tipping Radiometers

Cryogen usage

• CSO-JCMT Interferometer
• SHARC (original)