The Combined Array for Research in Millimeter-wave Astronomy (CARMA) is a 15 element heterogeneous millimeterwave
array developed and operated by a university consortium that will be expanded to 23 elements in 2008.
Commissioning began in August 2005 after completion of the relocation of antennas from the Owens Valley Radio
Observatory (OVRO) and the Berkeley-Illinois-Maryland Association (BIMA) arrays to a new high site and initial
scientific operations began in April 2006. The array operates in the 3-mm and 1-mm bands and has a maximum
resolution of 0.15 arc seconds. Most of the software and computing infrastructure for the array is new, allowing modern
technology to be introduced and to provide a common interface for the disparate antenna types. The new system is
proving to be both easy to use for routine observations and yet capable enough for the development of new observing
techniques by the experienced astronomer. Some of the details of the computing and software are described here, with
emphasis on the control system.
The Combined Array for Research in Millimeter-wave Astronomy (CARMA) comprises the millimeter-wave antennas of the Owens Valley Radio Observatory (OVRO), the Berkeley-Illinois-Maryland Association (BIMA) Array, and the new Sunyaev-Zel'dovich Array (SZA). CARMA consists of six 10.4-m, nine 6.1-m, and eventually eight 3.5-m diameter antennas on a site at elevation 2200 m in the Inyo Mountains near Bishop, California. The array will be operated by an association that includes the California Institute of Technology and the Universities of California (Berkeley), Chicago, Illinois (Urbana-Champaign), and Maryland. Observations will be supported at wavelengths of 1 cm, 3 mm, and 1.3 mm, on baselines from 5 m to 2 km. The initial correlator will use field programmable gate array (FPGA) technology to provide all single-polarization cross-correlations on two subarrays of 8 and 15 antennas with a total bandwidth of 8 GHz on the sky. The next generation correlator will correlate the full 23-antenna array in both polarizations. CARMA will support student training, technology development, and front-line astronomical research in a wide range of fields including cosmology, galaxy formation and evolution, star and planet formation, stellar evolution, chemistry of the interstellar medium, and within the Solar System, comets, planets, and the Sun. Commissioning of CARMA began in August 2005, after relocation of the antennas to the new site. The first science observations commenced in April 2006.
A new Combined Array for Research in Millimeter-wave Astronomy (CARMA) interferometer is being assembled from the existing Owens Valley Radio Observatory (OVRO), the Berkeley-Illinois-Maryland Association (BIMA) millimeter interferometers and the new Sunyaev?Zeldovich Array (SZA) at Cedar Flat, a site at 2,200 m altitude in the Inyo Mountains east of OVRO. The array will consist of 23 antennas of three different diameters, 3.5, 6.1 and 10.4 m, and will support observations in the 1 cm, 3 mm and 1.3 mm bands. The fist-light correlator is a flexible FPGA based system that will process up to 8 GHz of bandwidth on the sky for two subarrays consisting of 8 and 15 elements. The array configurations will offer antenna spacings from 5 m to 1.9 km allowing unprecedented high resolution and wide field imaging at millimeter wavelengths. Radiometers observing the 22 GHz water vapor emission line will be used to measure and correct for the water vapor induced path delay along the line of sight for each telescope and thereby minimize the time lost to “bad seeing”. This university based facility will emphasize technology development and student training along with leading edge astronomical research in areas ranging from Sunyaev-Zeldovich effect galaxy cluster surveys to studying protoplanetary disks.
Remote observing with Caltech's millimeter wave array at the Owens Valley Radio Observatory (OVRO) is being extended to use the graphical capabilities commonly available on computers today. To allow the instrument to be clearly presented to the user, a rich interface has been developed that combines the use of color highlights, graphical representation of data, and audio. Java and internet protocols are used to extend this interface across the Web to provide remote access. Compression techniques are used to enable use over low bandwidth links. This paper presents the design goals, implementation details, and current status of this effort with emphasis on the monitoring of the array.