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ApertureBuy the right telescope, not the biggest one

Instrument class

150–200 mm Dobsonian

The most aperture per euro anyone has yet arranged. A full-size rocker box on the floor, a tube you carry in two trips, and views that stop people mid-sentence.

Specifications for this class
Aperture150–200 mm
Focal ratiof/5–f/8
Typical weight20 kg
Setup time8 minutes
Learning curve2 out of 5
Price band€330–700
Useful magnification29× to 350× at 175 mm

What it does well

  • Enough aperture that globular clusters resolve into stars rather than staying fuzz
  • No mount to align: push it, and it stays where you left it
  • Nothing electronic to fail at −2 °C

What it costs you

  • Two trips outside, or one heavy one. This is what decides whether it gets used
  • The base is bulky in a way the tube is not — storage is the real constraint
  • Useless on a balcony: it cannot swing past a railing or reach anything high

Fit against each goal

  • Nebulae, clusters and galaxies, by eye · 5 out of 5

    The classic answer. Aperture is what deep-sky observing is short of, and this is where it stops being expensive.

  • The Moon and the planets · 4 out of 5

    Plenty of resolution. You will be nudging it along by hand every thirty seconds at high power.

  • Learn my way around the sky · 3 out of 5

    Star-hopping with a finder works well, but the field is narrower than binoculars.

  • Sharing it with children · 2 out of 5

    The eyepiece height wanders between standing and kneeling as you move around the sky.

  • Taking it with me · 1 out of 5

    It goes in a car and nowhere else.

Models in this class

Indicative European street prices with the date they were observed. Ordered by price. Links marked earn us a commission and cost you nothing extra.

  • Bresser Messier 6" Dobson

    €380seen 2026-08-17

    152 mm · 1200 mm focal length · f/7.9 · 19 kg

    With a 10 mm eyepiece: 120×, 1.3 mm exit pupil.

    Mount Full-size Dobsonian rocker box

    Eyepieces 25 mm and 9 mm

    Where to buy

    None of these links earn us anything.

  • Sky-Watcher Skyliner 200P

    €545seen 2026-08-17

    200 mm · 1200 mm focal length · f/6.0 · 25 kg

    With a 10 mm eyepiece: 120×, 1.7 mm exit pupil.

    Mount Full-size Dobsonian rocker box

    Eyepieces 25 mm and 10 mm

    The instrument most experienced observers name when asked what they wish they had bought first. Two trips outside, and worth both.

    Where to buy

    None of these links earn us anything.

See whether this class suits you →