A new method for making maps with unstable radio interferometers

Abstract

We present a new method for making 'hybrid' maps using data from unstable interferometers. Our approach is based on correcting errors occurring at individual telescopes, and is more general than previous ones in that it allows for different degrees of instability at each telescope as well as for varying signal-to-noise ratios in the visibility data on each baseline. The method was developed, and will be used, for the analysis of the data from the Jodrell Bank Multi-telescope Radio-Linked Interferometer (MTRLI). We show the results of tests on simulated data to indicate the quality of maps which can be made with the MTRLI using the new method, and present a hybrid map of the quasar 3C 309.1 made from actual MTRLI data at 1666 MHz.