Lying between Virgo and Scorpius in the zodiac, Libra is an ancient constellation. The stars now represent a weighing scale, as they did four thousand years ago in Babylon. But how did its brightest stars come to have names related to a scorpion's claws?

Autumn equinox and autumn sky, discoveries and discoverers, an ancient festival that marked the transition from the light to darkness. Can you identify them?

Years ago, if you weren't serious about being an astronomer, a good career-killer would have been hunting for exoplanets. It's different now. Stuart Clark tells the story from the first discovery of a planet orbiting another star to the current Search for Earth's Twin.

Mimas is named for a giant in Greek mythology, but Saturn's moon is no giant. It's less than 400 km (245 mi) across and the smallest body we know of that's rounded by gravity. The moon also has a bizarre resemblance to the Death Star in George Lukas's Star Wars films.

If you look at your calendar to find today's date, you can see the month, days of the week and maybe some appointments. But you're also looking at something that tracks Earth's journey around the Sun, reflects three thousand years of history and helps to hold our society together.

Flying fish live in warm oceans, and so do the mahi mahi fish. Sailors in the southern seas saw the flying fish using their side fins like wings to glide through the air – sometimes chased by hungry mahi mahi. Dorado (Mahi mahi) pursues Volans (Flying fish) in the stars of the southern sky.

Moon phases and eclipses are easily seen, but rather abstract to understand. The first section of this article lists the basic concepts with some links to diagrams. The sections that follow suggest resources for teachers, both lesson plans and short videos available online.

Our Solar System was the only one we knew. Astronomers used it to explain how star systems were made. But beware the theory based on only one example! We now know of thousands of planets around other suns, and the theories need revising. Here are a few of the astonishing planets we've found.

Interested in astronomy or space-related science projects? Forget the model of the Solar System – that's for young children. Here are a number of ideas from several sources which should be a help to students and educators.

Not everyone wants to plan a science fair, but science teachers still need to teach science. Projects are part of learning – not only learning science, but also learning transferable skills. The resources cited in this article aren't just for the fair, they could help you in the classroom too.