Accurate astrometry of southern pulsars

This thesis outlines the astrometric measurements of 10 pulsars using phase-referencing Very Long Baseline Interferometry (VLBI) employing telescopes in the Australian Long Baseline Array (LI3A) and Hartbeesthoek observatory. Observations spanned from 1993 to 2001. A parallax was measured for the Vela pulsar of ˜ìvÑ = 2.46 ¬¨¬± 0.24 mas placing the pulsar at a distance of 406=44-36 pc. This constitutes the first model independent measurement of the pulsar's distance. This is below the early distance estimates to the pulsar of 500 pc, and above some other more recent estimates. The proper motion was found to be ˜í¬¿˜í¬± cos ˜í¬• = -50.3 ¬¨¬± 0.4 mas yr-1 and ˜í¬¿˜í¬• = 29.0 ¬¨¬± 0.2 mas yr-1. This lies between proper motion measurements made using both optical astrometry and phase-referencing VLBI.