Sky-Watcher

Sky-Watcher Flextube 250P Collapsible Dobsonian

10 inches of aperture in a tube that collapses to two-thirds its length, the Dobsonian that gives you serious light-grasp and still fits in a car.

89/ 100

Polaris Score

#1 of 5 10-inch Dobsonian

See the breakdown ↓

Aperture

254mm

Focal Length

1200mm

Focal Ratio

f/4.7

Mount Type

Dobsonian

Optical Design

Dobsonian

Weight

27.5 kg

From$1,150

Lowest in 90 days

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Where to buy

Sky-Watcher USABest price$1,150→Amazon$1,150→Astronomics$1,150→Starizona$1,150→

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What it's built forOpen these in the simulator →

This telescope was built to gather light.

254 mm of aperture pulls in the faint light that galaxies and clusters live or die on. Point it up under a dark sky and objects that are rumors in smaller scopes resolve into real structure.

Sweet spot 190–320×Rewards dark skies

The view people remember

The Sombrero, brim and all.

A bright edge-on galaxy crossed by a sharp dark dust lane — the brim of the hat — one of the most distinctive shapes in the entire deep sky.

See The Sombrero Galaxy through this telescope →

Where else it shines

Rewards a dark sky

Andromeda Galaxy

Galaxy structure starts revealing — bright core, extended halo

Open view →

Easy first target

The Pleiades

Densely packed showpiece — hundreds of stars across multiple magnitudes

Open view →

Within reach

Orion Nebula

Stronger structure — embedded stars plus dark lanes within the core

Open view →

Also excellent on

Saturn

Sharp planetary detail — multiple bands, festoons, and surface variation

Open view →

✦

It is a light bucket, not a travel scope — the reach comes with real bulk and a dark-sky drive out of town.

01What it's good at

What it's best at — and the trade-offs.

Best at

✓254mm gathers roughly 55 percent more light than an 8-inch, the difference between glimpsing a galaxy and seeing its shape

✓The Flextube truss collapses the tube down for transport, then extends and locks in seconds with repeatable collimation

✓At f/4.7 it delivers bright, wide low-power views that make sweeping the Milky Way a pleasure

✓It keeps the Dobsonian virtues intact: no power, no alignment, point and observe

Trade-offs

!The open truss lets stray light and dust reach the optics, so a light shroud helps in bad locations

!f/4.7 is demanding on eyepieces and shows coma at the edge without a corrector

!It still weighs enough that the base and tube are separate two-part carries

!No tracking means re-centering by hand at high power

02In plain English

What These Numbers Mean

Aperture

254 mm (10 inch)

Ten inches collects about 1,300 times the light of your eye. Galaxies show shape and dust lanes, globular clusters resolve into stars, and the brighter planetary nebulae reveal internal structure from a dark site.

Focal length

1200 mm

Enough for 240x on planets with a 5 mm eyepiece, while a 30 mm eyepiece gives a wide 40x sweep. A single telescope that covers both ends of visual observing.

Focal ratio

f/4.7

Fast optics reach wide, low-power fields easily but demand well corrected eyepieces and regular collimation. Budget wide-angle eyepieces will show soft stars at the field edge here.

Optical design

Collapsible truss Newtonian

The tube collapses to roughly half its length for transport, which is the practical difference between a 10 inch that fits in a hatchback and one that does not. Expect to check collimation after each setup and to use a shroud on damp nights.

Weight

27.5 kg total

About 61 lb split between tube and base. Each piece is a manageable single carry, but this is a garden and driveway telescope, not a hiking one.

Mount

Manual Dobsonian base

Simple, steady and instantly ready with no power or alignment. You nudge to track, so at high magnification objects need regular small pushes and long exposures are not possible.

02The Polaris Score

How it scores, and why.

89/ 100

Sky-Watcher Flextube 250P Collapsible Dobsonian

#1 of 5 10-inch Dobsonian

Performance

Ease of use

Portability

Upgrade potential

Polaris weighs optical capability, how easy the scope is to live with, how portable it is, and how far it takes you before you outgrow it — not list price or brand.

03Who it's for