Which telescope should I buy as a beginner?

More people are put off astronomy by a bad first telescope than by anything else. The pattern is consistent: a wobbly tripod, a tiny finder, plastic eyepieces and a claim about magnification on the box. Buying on the two things that matter instead produces an instrument that shows you real detail for decades.

What you'll need

• A dark-ish site or a garden away from direct lights
• A red torch
• A star atlas or planetarium app
• Warm clothes — standing still at night is cold

Step by step

1. Understand aperture, and buy as much as you will carry.Aperture is the diameter of the main mirror or lens, and it decides how much light the telescope collects and how much detail it can resolve. Everything else is secondary. The largest telescope you will actually carry outside and set up is the right one; the largest one you can afford, that then lives in a cupboard, is not.
2. Ignore magnification claims completely.Magnification is a function of the eyepiece, and any telescope can be made to magnify absurdly at the cost of a dim, blurred, useless image. Useful maximum magnification is roughly twice the aperture in millimetres, and British atmospheric conditions often limit it well below that. A box advertising 525x is advertising that it is not a serious instrument.
3. Judge the mount as harshly as the optics.A telescope on a shaky mount is unusable — every touch sets it wobbling for several seconds and finding anything becomes impossible. Half the cost of a good beginner telescope is in the mount, and this is the thing cheap telescopes economise on.
4. Consider a Dobsonian first.A Newtonian reflector on a simple wooden alt-azimuth base. It gives far more aperture per pound than anything else, it is intuitive to point — push it where you want to look — and it is stable. A 150mm or 200mm Dobsonian is the standard recommendation for a first serious telescope, and it shows the Moon, planets, and a great many deep-sky objects properly.
5. Consider a small refractor for portability and planets.A lens-based telescope, typically 70mm to 100mm, on an alt-azimuth or equatorial mount. Sharp, low maintenance, needs no collimation, sets up in a minute, and is much smaller in aperture for the money. Excellent for the Moon, planets and double stars, and limited on faint objects.
6. Consider a Maksutov or Schmidt-Cassegrain for compactness.Folded optical paths give long focal lengths in short tubes. Very good on the Moon and planets, portable, and needs time to cool to outside temperature before the image settles.
7. Decide about a computerised mount honestly.GoTo mounts find objects for you and are genuinely helpful in light-polluted skies where you cannot star-hop. They cost money that would otherwise buy aperture, they need setting up correctly each session, and they need power. If you enjoy learning the sky, a manual Dobsonian teaches you more.
8. Budget for eyepieces and a decent finder.Supplied eyepieces are often mediocre. Two or three good ones — a low power for finding, a medium and a high — transform an average telescope. A red-dot finder or a right-angle finder makes pointing far less frustrating than the small straight-through finders often supplied.
9. Start with binoculars if you are unsure.A pair of 10x50 binoculars on a tripod shows the Moon's craters, the Galilean moons of Jupiter, star clusters, the Andromeda galaxy and a great deal else, costs a fraction of a telescope, and is never wasted. Many experienced observers use binoculars more than a telescope.
10. Join a local astronomical society before buying.Almost every part of Britain has one, most hold public observing evenings, and you will get to look through half a dozen different telescopes and ask their owners what they wish they had bought. It is the single best thing you can do before spending money.
11. Buy from a specialist dealer.Astronomy retailers sell instruments rather than magnification numbers, offer sensible advice, and take second-hand stock. The used market is excellent, because a great many telescopes are bought, used twice and sold.

Tips

• Set the telescope outside half an hour before observing so it cools to air temperature. A warm mirror produces a soft, shimmering image.
• The Moon is spectacular in any telescope and is the best first target, but not when full — the shadows along the terminator are what show the relief.
• Learn the sky with your eyes and binoculars first. Knowing where things are is what makes a telescope useful.
• A cheap red LED torch protects your dark adaptation and costs almost nothing.
• Buy second-hand. Telescopes hold up extremely well and the market is full of near-unused equipment.

Common mistakes

• Buying on advertised magnification — It is a marketing number achieved with a barlow and a tiny eyepiece, and the image at that power is dim and blurred. Aperture and mount are what matter.
• Buying more telescope than you will carry outside — The telescope that gets used is the one you can set up in five minutes. A large instrument that lives in the loft shows you nothing.
• Expecting the views from photographs — Long-exposure images collect light for hours. Through an eyepiece, galaxies and nebulae are subtle grey shapes — the reward is real and it is different, and knowing that in advance prevents disappointment.

Alternatives

• 10x50 or 15x70 binoculars: The best first purchase for most people. Wide field, easy to use, great on clusters and the Moon, and useful for everything else in daylight. Anything above 10x needs a tripod.
• 150–200mm Dobsonian: Maximum aperture per pound on a stable, intuitive mount. Bulky and heavy, and the standard answer for a first telescope that will not disappoint.
• 80–100mm refractor: Portable, sharp, no collimation, quick to set up. Less capable on faint deep-sky objects for the money.
• 127mm Maksutov: Compact and excellent on the Moon and planets. Long cool-down and a narrow field of view.
• GoTo alt-azimuth with a small tube: Finds objects for you, which helps under city skies. Spends money on electronics rather than aperture, and needs correct alignment each time.

Questions people ask