www.aao.gov.au/local/www/pns/pns.html

Planetary Nebulae (PNe) are excellent probes of a distant galaxy's rotational dynamics... We have proven that two counter-dispersed images contain the information needed to obtain distances and dynamics in a single observation -- to our knowledge the only way of doing so!

PARTICIPANTS:

• K. Taylor, Anglo-Australian Observatory
• M. Arnaboli, Osservatorio di Capodimonte, Naples
• N. Douglas & K. Kuijken, Kapteyn Institute, The Netherlands
• K. Freeman & T. Axelrod, Mt Stromlo and Siding Springs Observatory, Australia
• R. Gilmozzi, ESO, Garching

DEMONSTRATION:

The following pair of images illustrate the idea (these data were taken at the WHT in April 1997). Click on them to `blink' them. It will be obvious that the displacement of various PNe differs (notice especially how the shape of groups of objects changes). These differences arise because the PNe have different velocities.