ATCA Observing Characteristics Calculator
This page provides a means of estimating the characteristics of
ATCA observations with the
Compact Array Broadband Backend (CABB)
system. The calculator allows both available and planned CABB modes to be selected: please check the
CABB webpage for which modes have been implemented.
(The pre-CABB sensitivity calculator is still available and may be useful for those considering archival ATCA data.)
The calculator 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 calculations of antenna efficiency as a
function of frequency, revised (CABB era) 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.
For CABB it is assumed that
the full 2GHz is available at 4GHz and above, and that
500MHz is available at 20cm and 13cm. RFI may reduce the usable bandwidth,
particularly at 20cm.
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: 14-Nov-2009.
This tool was originally developed by Steven Tingay and Lister Staveley-Smith, and developed further by Bob Sault and Phil Edwards.