First night · 4 minute read
Reading a star chart
Why east is on the left, what the circles mean, and how to hold a chart so the sky matches.
The chart is a sky seen from below
A map of the ground is drawn as if you were looking down on it, so east is on the right. A sky chart is drawn as if you were looking up, so east is on the left. Hold it over your head, with the north edge towards north, and it lines up with the sky.
The parts of the chart
- The outer circle is the horizon, all the way round.
- The centre is the zenith, the point straight overhead.
- Rings in between show height above the horizon: halfway out is roughly halfway up.
- Larger dots are brighter stars. Start with those and use the lines of the constellations to step to fainter ones.
Try it tonight
Our Sky Tonight chart is drawn exactly this way, for our roof, at any time you choose. Print it, or keep it open on a phone in red-light mode so it does not spoil your night vision.
