Naked eye, binoculars, telescope

The best first instrument is your own eyes: learning the sky with the naked eye makes any instrument much easier to use later.

Binoculars

A pair of 7×50 or 10×50 binoculars (magnification × lens diameter in millimetres) is cheap, portable and shows lunar craters, Jupiter's moons, the Pleiades, the Andromeda Galaxy and hundreds of star clusters. Beyond 10× you need a tripod.

Telescopes

• Aperture (the diameter of the lens or mirror) matters, not magnification: more aperture means more light and more detail.
• Refractors (lenses): rugged and maintenance-free. Reflectors (mirrors): more aperture for the same price.
• A reflector on a Dobsonian mount is often the best way to start: simple to use and very bright.
• Beware of boxes promising "500× magnification": that is marketing, not quality.
• The mount matters as much as the optics: if it shakes, the view is useless.

Before buying, if you can, join a public night of an astronomy club: you will be able to try several instruments.