In this talk I will describe some of the results of my recently completed PhD research that involve radio continuum and maser
observations with very long baseline interferometry (VLBI). I will use multi-epoch observations to derive the astrometry of
masers and use them to trace the surroundings of old and dying stars. Three main topics will be touched upon, connected by the
themes of VLBI astrometry, stellar masers and stellar evolution:
1, Results from a new observing technique to conduct precise VLBI astrometry at the ionosphere influenced radio frequencies,
2, Trigonometric distance measurements to long period variable evolved (AGB) stars, and what these tell us about stellar
evolution, and
3, Observing the shape and motion of jets around water fountains, which are intermediate-mass stars undergoing their final
evolution to planetary nebulae. We will use VLBI maser measurements to see how water fountain jets might shape the complex
structures found around PNe.
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