TELCAL: the ALMA On-Line Calibration Software

Broguiere, Dominique

On-line calibration groups all the operations needed to maintain the ALMA interferometer optimally tuned to successfully execute the planned observations. On-line calibration primarily deals with 1) the measurement of the atmospheric absorption and of the phase radiometric correction, 2) the pointing and focus offsets computation, 3) the delay measurements, 4) the solving of antenna position, 5) the monitoring of phase and amplitude on an astronomical calibrator source. The results of the calibrations are used in quasi-real time by the ALMA Control System.

The first ALMA antennas were put into operation in Chile in 2009 and since this date, TELCAL has been used for all the basic calibration operations and is still being improved following the project advancement.

We describe in this poster the calibrations done by TELCAL, its relationships with the other ALMA software subsystems and, briefly, the architecture of the software based on CORBA.

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