NAM logo, by David Le Conte

JIVE/EVN real-time fringe verification

Derek J. McKay (Telescope Technologies Ltd)

Very Long Baseline Interferometry (VLBI) is one of the most logistically complicated of all the astronomical sciences, and the European VLBI Network (EVN) is a prime example. Because interferometric fringes are not verified until long after the experiment has finished, a near-real-time feedback system is being developed by the Joint Institute for VLBI in Europe (JIVE).

The basic principle behind this facility is that a small data sample is captured automatically at each EVN station. Once acquired, the data are transmitted to a central site using conventional Internet connections and the standard File Transfer Protocol (FTP). This transmission generally takes less than one minute. At the FTP repository, software automatically detects and processes the data and makes the results available on the World Wide Web.

A successful result ensures that the station has correct source coordinates and epoch, good telescope pointing solutions, well-known antenna position, correct frequency, bandwidth, spectral inversion, polarisation and small clock offsets. By fully automating the system, it is envisaged that it will make a significant contribution to the reliability of the EVN.

Maintained by Ian Howarth