In the treaties between the United States and the host countries, Spain and Australia, provision is made for the host countries to use the DSN for independent scientific activities on a non-interference basis. It has been recognized that the DSN facilities can make unique contributions to radio astronomy. Proposals for VLBI investigations are generally submitted to the US National Radio Astronomy Observatory for evaluation. Other astronomical investigations may be proposed to the Manager, TMOD Technology and Science Office, who will obtain competent outside peer review. The classification is necessarily fuzzy, but helps to identify instrumentation requirements.
Some measurements combine two or more techniques.
Common to all measurements is the need to coordinate operation of often specialized recording equipment with antenna movements, sometimes in complicated sequences. Radio Continuum Measurements Broadband detectors combined with band-limiting filters are used to record signals which have no significant variation with frequency over the range of the filter. The measurements may involve high time resolution, such as in studies of pulsar timing. Connected Element Interferometry High angular resolution is achieved by combining the signals from two or more antennas. Very Long Baseline Interferometry Antennas at widely seprated geographical locations can be combined into a synthetic radio telescope by locally recording the signals on high capacity magnetic tapes and combining the signals afterwards.