Every beginner telescope box shouts about magnification, usually a number like 600x. Ignore it. That number is almost meaningless, and it is the main reason first telescopes disappoint.

For planets, aperture — the diameter of the main lens or mirror — is the spec that matters most. More aperture gathers more light and resolves finer detail. A 90 millimetre refractor or a 130 millimetre reflector is a sensible starting point that will show Saturn's rings, Jupiter's cloud belts, and Mars's polar cap.

The mount matters as much as the optics. A wobbly tripod turns every touch into a shaking image at planetary magnifications. A stable alt-azimuth or Dobsonian mount that moves smoothly is worth more than a slightly larger telescope on a flimsy stand.

Realistic magnification for planets is roughly 100x to 200x on most nights, limited by the atmosphere rather than the telescope. Any telescope advertising far more than that is selling a number your sky cannot support.

Before buying, consider a Dobsonian reflector for the best aperture per pound, or a small refractor if you want something low-maintenance and portable. Either way, budget for one or two decent eyepieces rather than a box full of accessories.

Finally, try before you buy if you can. A local astronomy club will let you look through different telescopes and, just as importantly, show you what planets actually look like through a real eyepiece — small, bright, and wonderful.

Eyepieces deserve a word of their own, because they determine magnification and comfort. A telescope that comes with one or two decent Plossl eyepieces will serve you better than one bundled with a box of cheap accessories, including the low-quality Barlow lenses and filters often thrown in to inflate the package. A good starting pair is a low-power eyepiece for finding objects and a medium-power one for planets, roughly 25 millimetres and 10 millimetres in a typical beginner telescope. Buy additional eyepieces later, once you know which magnifications your skies actually support, rather than buying a full set on day one. Quality over quantity applies to eyepieces just as it does to telescopes.