In this workshop, we will look at how observing celestial occurrences has helped us build an understanding of the universe. Using scientific investigative approaches and examining scientific methods, we will look closely at the moons of Jupiter to determine the mass of Jupiter. This workshop will look at how we can measure distances in space, angular distances using telescopes and calculating basic relationships. To finish the workshop we will have a session in the planetarium to view both Jupiter and Saturn and try and measure the distance from one of the moons to the planet.