This repository contains material for the practical numerical sessions for the 2023 CISM school on “Fluid Mechanics of Planets and Stars”. These materials explore the use of the open-source PDE solver Dedalus for solving problems related to geophysical and astrophysical fluid dynamics. You can view the notebooks online at the provided HTML links, open and execute them via Google Colab, or download them to run locally after installing Dedalus on your computer.