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CSO: The Caltech Submillimeter Observatory

Link to CSO Web site

I. General project/facility description

  1. Overview of the facility/project
    The CSO consists of a 10.4m diameter Leighton dish, in an astrodome, sited on Mauna Kea, Hawaii, at about 14,000 feet elevation. The observatory is fully equipped with receivers and bolometer cameras to service the complete spectral range, between about 190 GHz (1.8 mm) and 950 GHz (0.34 mm). At sea level, in Hilo, there is a 7,000 square foot office and laboratory building. The CSO also owns 6 bedrooms at the mid-level dormitory.

  2. Managing institution and organization
    The CSO is owned and managed by Caltech. There is a lease agreement with the University of Hawaii (UH) which provides for 10% of observing time to UH. Also the University of Texas (UT) is a minor partner. The CSO is operated by a director with a staff of about 20, split between Pasadena and Hawaii. There is an external Time Allocation Committee (TAC) which also functions as an advisory board to the director.

  3. Funding source(s)
    The primary funding source for the CSO is the NSF. Currently the funding is about 90% NSF, 5% Caltech (JPL) and 5% UT (private).

  4. Construction history and cost
    The total cost of construction of the CSO (1984-1987) in 2003 dollars was about $14M (~$11M from NSF), using an inflation factor of 1.6 (CPI). This includes the cost of the telescope, dome, buy-in to the site, the initial set of receivers, the 6 dormitory rooms at the mid-level facility and the Hilo building ($1.5M - private).

  5. Operational history and cost
    Operation cost largely has been borne by the NSF from about 1987 to the present and, taking inflation into account, has remained fairly constant at about $2.5M/yr (2003 dollars).

    When the LSAT becomes operational as a world class facility (~2010), it will replace the CSO as a world-leading facility and it is anticipated that NSF anticipated that NSF would not support both telescopes. However, the CSO might very well still occupy a critical niche and would remain open, funded by other sources. Options might include:

II. Technical details

  1. Specifics of telescope/instrument
    The telescope has a diameter of 10.4 m and achieves a surface accuracy of about 17 µ (RMS) when operated with the surface real-time correction scheme (DSOS). This scheme adjusts the surface as a function of elevation, the errors being corrected out by heating/cooling of the panel support rods, resulting in control of the panel positions. The error maps at each elevation are pre-determined by the CSO point source mapping, holography device.

    Facility continuum bolometer instruments include BOLOCAM, 144 pixels operative over 26 sq arcmin in the 1-2 mm range, and SHARC II, 384 pixels covering 2.3 sq arcmin in the 350-450 µ (700-890 GHz) range. Five low noise heterodyne receivers offer capabilities across the 350 µ to 1.6 mm (180-900 GHz) band. Several non-facility instruments are also used; HERTZ (U. of Chicago); SuZie (Stanford S-Z bolometers) and FIBRE (Goddard F-P spectrometer).

    The CSO also participates in short-baseline interferometry with the James Clerk Maxwell Telescope (JCMT), located approximately 180 meters from the CSO and the SMA.

  2. New capabilities anticipated/planned in next 5-10 years

III. User profile

  1. % of "open skies" time
    About 50% "open skies" time (see below).

  2. Institutional affiliations of users
    The CSO provides 50% of the observing time to the National/International community through a 6 monthly call for proposals and a nationally constituted TAC. The remaining time is allocated to U. Texas (7.5%), U. Hawaii (10%) and Caltech (32.5%). Usually, annually, there is one month shut-down for major engineering and four nights/month for receiver engineering or telescope optimization.

    In 2003, there were 186 users, of which 50 were from Caltech. 44 institutions in the US and worldwide were represented by users.

  3. Student access, involvement, usage
    In 2003, 57 (roughly 1/3) of the users were students and 6 students were directly involved in building detectors/receivers.

IV. Science Overview

  1. Current forefront scientific programs

  2. Major discoveries (through 1999)

  3. Science highlights of last 5 years

  4. Main future science questions to be addressed

V. Education/Outreach activities

  1. Visitor facility
    As one of the Mauna Kea Obseravatories, the CSO is affiliated with the Onizuka Center for International Astronomy and makes regular financial, content, and planning contributions to the Onizuka Visitors' Information Station which hosts over 100,000 Mauna Kea visitors annually. Members of the CSO staff regularly participate in events at the Visitor Information Station and elsewhere in Hawaii. In 2004, activities included career talks at schools, mentoring science fair participants, supervising local student employees and the production of display materials, PPT presentations and videos.

  2. Student programs
    In addition to the students who use the CSO for their research or work on instrument/receiver development, members of the CSO staff in Hawaii supervise undergraduate students on site.

VI. Documentation/website URLs

  1. URL of facility website:
  2. URL of EPO website
  3. URL(s) of any brief overviews of project/facility
  4. URL(s) of miscellaneous documentation

This page created and maintained for the RMSPG by Martha Haynes
Last modified: Wed Feb 2 21:54:09 EST 2005. Reviewed by T. Phillips.