ATCA Observing Characteristics Calculator
This page provides a means of estimating the characteristics of an ATCA observation. This includes the theoretical RMS noise in an resultant image (Stokes I, Q, U, or V). The corresponding brightness temperature sensitivity is also calculated. These estimates are based on the expressions appearing in the ATNF technical document AT/01.17/025, the latest calculations of antenna efficiency as a function of frequency, the latest measurements of system temperature as a function of frequency, and simulations of the effects of different weighting schemes on images made with different ATCA configurations. In calculating the effects of weighting, 30 second samples and Miriad default cell and image sizes were assumed. It is also assumed that the central 81.25% of the bandwidth is used for continuum imaging, corresponding to using the birdie option in Miriad task atlod.
It is assumed that the nominated integration time is evenly spread over a 12 hour observation. Note the time given is the integration time: this does not account for overheads involved in calibration. Depending on the calibration scheme used, these overheads might vary between 5% for simple 20cm observations, to 50% for 3mm observations.
Page last updated: 13-Jun-2007.
This tool was originally developed by Steven Tingay and Lister Staveley-Smith, and developed further by Bob Sault.