Circumstellar disks and the search for neighbouring planetary systems.

The recent discoveries of planets orbiting several 'mature' stars bring new life to the question of just how common other planetary systems might be. Observations of very young stars provide a way to address this question and suggest that a significant number of such stars harbour conditions appropriate for the formation of planetary systems like our own.

Active stabilization system for Fabry-Perot interferometers.

We describe an optical technique to monitor and stabilize the cavity spacing of a Fabry-Perot interferometer, allowing it to be used as a tunable filter.