Stars and Sky Landmarks
What you see when you look up at a clear sky: familiar shapes, official divisions, and the stars themselves.
Asterisms
Popular star patterns with no official status — the Big Dipper, the Summer Triangle...
Constellations
The 88 official divisions of the sky adopted by the IAU, from antiquity to today.
Stars
The Sun is just one star among hundreds of billions: classification and life cycle.
Exoplanets
More than 5,000 worlds detected outside the solar system: detection methods and the habitable zone.
Eclipses
Solar and lunar eclipses, why they are so rare, and the Saros cycle.
Astrobiology
The search for life elsewhere: extremophiles, subsurface oceans, and the Fermi paradox.
Before the telescope, binoculars
For spotting clusters, double stars, and large sky landmarks, a good pair of binoculars is often the best first instrument — our guide helps you choose.
Best astronomy binoculars for beginners →