Notes on LBA amplitude calibration

These pages are intended to provide advice to LBA users on amplitude calibration of LBA data. Note that Chapter 9 of the AIPS Cookbook is a useful general guide for calibration and analysis of VLBI data. However, amplitude calibration of LBA data often requires special treatment, as measurements of system temperature (Tsys) and other calibration data may not be available for all telescopes.

Unfortunately, calibration of VLBI data is not as simple as calibration of data from a compact interferometer. Sources which are not variable are normally heavily resolved with VLBI, and sources which have compact, simple VLBI structures are almost all variable, so there are no good “primary calibrators” for VLBI.

The exact steps involved in LBA amplitude calibration depend on whether data was correlated before 2010, or after 1 January 2010. (NB a lot of experiments observed in 2009 were correlated in 2010.)

Data correlated pre-2010

Data correlated since 1 January 2010 and general strategies for amplitude calibration for all data (pre- and post-2010).

ANTAB files for LBA data

Table of nominal sensitivities by telescope/frequency