Some people are still upset that Pluto isn't considered a planet any more. But was it ever really a planet?

A dwarf planet so far away that the Sun would look like a exceptionally bright star, so cold that its atmosphere is frozen for most of its year. This is Pluto, former planet, and now the gateway to the Kuiper Belt.

NASA's New Horizons is on its way to visit Pluto, but it has a long way to go yet. Meanwhile here's a profile of dwarf planet 134340 Pluto, largest object in the Kuiper Belt and former planet. It has a lot of titles - and moons - for something so small.

The Pleiades - the Seven Sisters - were shown in star catalogs six thousand years ago. Visible from northern and southern hemispheres, probably every culture that ever watched the sky had a name for them. But what is this group of stars? And are there actually seven of them?

Saturn's rings, spiral galaxies, solar flares. Astrophotography has shown us some wonderful images, but it's more than pretty pictures. It has allowed us to discover objects too dim for the human eye to see. Partnered with spectroscopy, it moved astronomy from mapping to understanding the stars.

A flying horse on feathered wings - it's the constellation Pegasus. You can spot it by its most noticeable feature, the Great Square of Pegasus, though one star of the square belongs to poor Princess Andromeda. There's also a star in Pegasus very like our Sun with a planet circling it.

A mile above the California desert stands Palomar Observatory. Its 200-inch mirror was officially impossible to make, but George Ellery Hale's vision inspired a nation in the grip of the Great Depression and became the jewel in the crown of astronomy for the second half of the twentieth century.

The Sun is the star of the Solar System and makes life on Earth possible. But it's also a danger to our technological civilization. Learn all about our fascinating star in the beautifully illustrated “Our Explosive Sun.”

The stars of Orion have been part of humanity's mythscape for thousands of years. Seven bright stars outline the hunter's body. One of them is a supergiant nearing the end of its life. Yet just visible to the unaided eye is a vast stellar nursery where the next generation of stars is forming.

Tromsø, far to the north of Norway, attracts summer visitors to see the midnight sun and winter visitors to see the aurora borealis. The Northern Lights Planetarium is the northermost planetarium in the world. It's worth a visit at anytime, but extra welcome if it's too cloudy to see the sky.