Stellar Cartography
50,000 stars from the Gaia catalogue, two views of the same data
The European Space Agency's Gaia satellite has measured the positions, distances, and colours of over a billion stars. This interactive explores 50,000 nearby stars - first as they appear in the sky, then rearranged by temperature and brightness to reveal the hidden structure of stellar evolution.
50,000 STARS FROM THE GAIA DR3 CATALOGUE WITHIN 200 PARSECS. PRESS SPACE TO TOGGLE BETWEEN SKY VIEW AND HR DIAGRAM. SCROLL TO ZOOM, DRAG TO PAN.
Category
Scientific Data Visualisation
Audience
General / Science-curious. Anyone curious about astronomy or data visualisation. No prior knowledge required - the transition itself teaches you what the HR diagram reveals.
Technology
- WebGL (GL_POINTS)
- Gaia DR3 Archive
- Python (data processing)
- Next.js
Data
- ~50,000 stars
- Within 200 parsecs
- Gaia DR3 release
The Challenge
How do you make a billion-star catalogue comprehensible? Gaia DR3 contains precise measurements of 1.8 billion stars, but raw data at this scale is meaningless without structure. We needed to find the visual arrangement that reveals the hidden physics.
Background
The Hertzsprung-Russell diagram is astronomy's most powerful classification tool - it plots stars by temperature against brightness. When you do this, stars don't scatter randomly. They fall into distinct regions that correspond to different stages of stellar evolution.
The diagonal band is the main sequence, where stars spend most of their lives fusing hydrogen. Above it are the red giants - stars that have exhausted their core hydrogen and expanded. Below and to the left are white dwarfs - the dense remnants of dead stars.
Approach
We query 50,000 nearby stars from the Gaia archive, compute their absolute magnitudes from parallax measurements, and present them in two views: as they appear in the sky, and as they sit on the HR diagram. The animated transition between these views is the key explanatory moment.
Each star is coloured by its temperature - blue-white for the hottest, yellow for Sun-like stars, orange and red for cooler stars. The size reflects brightness. These visual encodings remain consistent across both views, so you can track individual stars as they move.