Learning catalogue
Learn astronomy by questioning the data.
Each lesson connects what you can see in the viewer to the measurements behind it. The aim is not just to name a concept, but to learn how real data makes that concept visible and where the data needs care.
First lesson
The Hertzsprung-Russell diagram
One of astronomy's most powerful maps, built from real star data: temperature, luminosity, stellar populations, and the limits of what a sample can show.
Open the lessonLesson
Star clusters: families of stars
Fly between real clusters, from stellar nurseries to ancient globulars, and see how age, gravity, and the galaxy shape stellar families.
Open the lessonLesson
The radio bubble
Explore an idealised sphere of human radio signals and ask which nearby stars those signals could have reached.
Open the lessonFiction meets real data
The astrophage infestation
Follow an unofficial story-led exercise inspired by Andy Weir's Project Hail Mary, using real nearby stars to explore local stellar geography.
Open the lessonResearch questions
After the lessons, ask what the data might be hiding.
Open investigations turn observations into testable questions. They are designed for students and independent learners who are ready to compare views, check assumptions, and treat uncertainty as part of the work.
Our approach
Real data, carefully questioned.
Gaia gives the site its foundation: a vast public map of the sky, with measurements that let us estimate where many stars really are in 3D. But real data is not perfect truth. It has gaps, errors, selection effects, and assumptions.
The strongest lessons use those limits as teaching material. A feature in the viewer is most interesting when you can ask whether it comes from the stars, from the sample, or from the way the data is being shown.