Sky-Watcher Dobson 10" Flex Tube 254/1200 telescope (SW-1311)

Sky-Watcher is a global leader in telescope manufacturing, particularly renowned for Newtonian models on Dobsonian mounts. The company has consistently prioritized top-quality optics, which is reflected in the stunning images of the universe their telescopes deliver and in their excellent reputation among astronomers worldwide. With experience dating back to 1990, Sky-Watcher produces Dobsonians that are elegant, mature, classic in design, and among the most affordable on the market. While there are many imitators, none match Sky-Watcher’s skill at creating telescopes that are both optically excellent and accessible to a wide range of users.

This is a large Newtonian reflector with a 10-inch (254mm) aperture and a 1200mm focal length. The optical tube is mounted on a very stable Dobsonian alt-azimuth mount. This fast Newtonian is ideal for observing nebulae and deep-sky objects under dark skies, but its large aperture also makes it excellent for detailed views of planets and the Moon. Despite its impressive capabilities, this telescope remains relatively affordable and is recommended for beginners and demanding amateur astronomers alike.

Pyrex Primary Mirror
All Sky-Watcher Dobson 10” telescopes are equipped with a primary mirror made from PYREX, a glass with very low thermal expansion, which ensures higher image quality than mirrors made from standard glass.

Collapsible Design
Sky-Watcher’s design is unique on the market—large Dobsonian telescopes can be collapsed for storage, saving significant space. This is accomplished with sliding tube sections, with no need for tools or disassembly. The telescope can be ready for observation in seconds. The precision of the mechanism means you do not need to re-collimate after every setup.

Mount
The Dobsonian mount is simple and highly stable, allowing for smooth rotation in both azimuth and altitude. The telescope is held securely in a fork mount, with the entire upper section rotating at the base. The low center of gravity and rigid materials provide much greater stability compared to equatorial mounts.

Focuser
This model features a 2" Crayford focuser with a 1.25" adapter. The Crayford design ensures smooth, backlash-free focusing. Both a 2" extension tube and a 1.25" extension/adapter are included (use one at a time). The focuser is compatible with Sky-Watcher autofocuser drives.

Astronomical Observations

A 10-inch (25cm) aperture provides powerful observation capabilities, including:

Solar System:

• Surface details on the Moon smaller than 1 km

• Sunspots and solar granulation clearly visible

• All Solar System planets

• Phases of Mercury and Venus, Venusian atmospheric detail with a gray filter

• Major surface features and polar caps on Mars

• Jupiter’s atmospheric belts, Galilean moons, and shadow transits

• Saturn’s rings (Cassini Division), atmospheric bands, and smaller moons

• Uranus and Neptune as small blue disks

• Tracking many asteroids

• Observing faint comets and their structure

Stars:

• About 6.5 million stars across the sky, down to about magnitude 15.5

• Double and multiple stars with separations greater than 0.6"

• Beautiful star colors

Deep-Sky Objects:

• All Messier catalog objects, plus hundreds of NGC and IC objects

• Hundreds of globular clusters, many resolved to the core

• Thousands of open clusters with distinct structural features

• Hundreds of nebulae, with spectacular detail in the brightest ones

• Hundreds of galaxies with visible structures, spiral arms, and disk orientation

• Structure and build of many planetary nebulae, with high contrast using nebula filters

• Subtle details of supernova remnants

Because of its 25cm mirror, objects are much clearer and more detailed than in smaller (130mm or 150mm) telescopes. However, larger telescopes are more sensitive to light pollution, atmospheric stability, and optical collimation accuracy. To get the best images with telescopes 20cm and larger, keep these factors in mind. The f/4.8 focal ratio also means good quality eyepieces are recommended.

Terrestrial Observations
This type of telescope is not ideal for terrestrial observing. To produce an upright image, an erecting lens must be used. With such a lens and the Dobsonian mount, it can function as a simple terrestrial viewer. The stable, easy-to-use Dobsonian mount is also suitable for tracking airplanes at cruising altitude.

Warning: When using solar filters on Sky-Watcher Dobson Flex Tube telescopes, always use a light shield to prevent sunlight from entering the tube from the side. Failure to do so can damage the filter, the telescope, or, most importantly, your eyesight. Always prioritize safety during solar observation.

Included Accessories

• 1.25" Super Plössl eyepieces: 25 mm and 10 mm

• 9x50 finderscope

Specifications

Catalog Number: SW-1311
Optical Design: Newtonian
Mount Type: Dobsonian
Aperture: 254 mm
Focal Length: 1200 mm
Focal Ratio: f/4.8
Limiting Magnitude: 14.6
Maximum Useful Magnification: 508x
Maximum Resolution (Rayleigh): 0.56"
Maximum Resolution (Dawes): 0.46"
Light Gathering Power: 1317x
Tube Weight: 15 kg
Mount Weight: 12 kg
Total Weight: 27 kg
Tube Length: 800 mm
Tube Diameter: 290 mm
Tripod Type: Dobsonian
Tripod Height: 740 mm
Mount Control: Manual
Focuser Type: Crayford
Focuser Diameter: 2"
Focuser Micro-motion: No
Secondary Mirror Diameter: 58 mm
Warranty: 60 months