Sky-Watcher BK 150/750 OTAW Refractor Optical Tube (SW-2006)

Sky-Watcher BK 150/750 OTAW Achromatic Refractor Optical Tube (SW-2006)

The Sky-Watcher BK 150/750 OTAW is a large-aperture achromatic refractor featuring a 150 mm objective lens and a 750 mm focal length. Its combination of a generous aperture and relatively short focal length provides an exceptionally wide field of view, making it an excellent choice for observing large open star clusters, expansive nebulae, and sweeping sections of the Milky Way.

Despite its large objective, the telescope remains relatively lightweight and compact, making transportation and storage straightforward. It is also an excellent option for beginners, as its wide field of view makes locating celestial objects significantly easier.

The telescope includes a 9×50 optical finder and tube rings with a dovetail plate for easy mounting on a compatible telescope mount.

While it provides enjoyable views of the Moon, the Sun (only when used with a properly certified solar filter), and the planets, its greatest strength lies in observing wide star fields and extended deep-sky objects. When paired with suitable eyepieces, it can deliver fields of view comparable to wide-angle binoculars while offering the light-gathering power of a telescope.

Its wide-field capabilities also make it an excellent instrument for observing comets with long tails, monitoring variable stars visually, and exploring brighter galaxies, globular clusters, and other deep-sky objects. In addition, the optical design makes it well suited for terrestrial observation.

Key features

• 150 mm achromatic refractor.

• 750 mm focal length.

• Fast f/5 optical system.

• Wide-field visual observation.

• Ideal for large nebulae, star clusters, and the Milky Way.

• 2-inch rack-and-pinion focuser.

• Compatible with Sky-Watcher electronic focus motors.

• 90° 2-inch mirror diagonal included.

• 9×50 optical finder.

• Tube rings with Vixen-style dovetail.

• Suitable for both astronomical and terrestrial observation.

Achromatic optical system

The telescope uses a classic two-element achromatic refractor design that delivers bright, sharp images with excellent overall optical performance.

With its 150 mm aperture, the telescope gathers approximately 459 times more light than the unaided human eye, allowing observation of objects down to approximately magnitude 13.5 under dark skies.

Its resolving power enables separation of double stars with angular distances greater than approximately 0.77 arcseconds (Dawes criterion).

Recommended mount

The optical tube is supplied without a mount.

For stable operation, a sturdy alt-azimuth mount equivalent to at least the Sky-Watcher AZ4 (preferably with steel tripod legs) is recommended.

Focusing system

The telescope features a 2-inch rack-and-pinion focuser supplied with a 1.25-inch adapter.

A premium 90° 2-inch mirror diagonal is included, allowing comfortable astronomical viewing.

The focuser is compatible with Sky-Watcher electronic focus motors as well as compatible aftermarket focus motor systems.

Astronomical observing capabilities

Solar System

For bright Solar System objects, using the supplied aperture mask can help reduce the visible effects of chromatic aberration.

The telescope is capable of observing:

• Lunar surface features approximately 1–1.5 km in size.

• Sunspots and their structure (only with an appropriate certified solar filter).

• All planets of the Solar System.

• Phases of Mercury and Venus.

• The disk of Mars.

• Jupiter's cloud belts and Galilean moons.

• Saturn's rings and Titan.

• Uranus and Neptune as stellar disks.

• Asteroid movement against the background stars.

• Bright comets.

Stars

The telescope allows observation of:

• Approximately 1.1 million stars down to about magnitude 12.5.

• Double and multiple stars separated by more than approximately 1.2 arcseconds.

• The colors of the brightest stars.

Deep-sky objects

The BK 150/750 is capable of observing:

• Nearly all Messier catalog objects.

• Hundreds of globular clusters.

• Hundreds of open clusters.

• Bright nebulae.

• Bright galaxies.

Terrestrial observation

The optical design also performs very well for terrestrial viewing.

When used with an erect-image prism diagonal, the telescope becomes a high-quality spotting scope suitable for long-distance observation and photography at its native focal length.

Included accessories

• 90° 2-inch mirror diagonal.

• Vixen-style dovetail plate.

• Tube rings.

• 9×50 finder scope.

• 2-inch rack-and-pinion focuser with 1.25-inch adapter.

• Super Plössl 25 mm eyepiece.

• Super Plössl 10 mm eyepiece.

Technical specifications

General

• Catalog number:

  • SW-2006.

• Product series:

  • Sky-Watcher StarTravel.

• Optical design:

  • Achromatic refractor.

• Mount:

  • Optical tube only (no mount included).

Optical specifications

• Aperture:

  • 150 mm.

• Focal length:

  • 750 mm.

• Focal ratio:

  • f/5.

• Limiting stellar magnitude:

  • 13.5.

• Maximum useful magnification:

  • 300×.

• Rayleigh resolution:

  • 0.95 arcseconds.

• Dawes resolution:

  • 0.77 arcseconds.

• Light-gathering power:

  • 459×.

Optical tube

• Tube weight:

  • 9.5 kg.

• Tube length:

  • 650 mm.

• Tube diameter:

  • 150 mm.

Focuser

• Type:

  • Rack-and-pinion.

• Diameter:

  • 2 inches.

• Fine-focus reduction:

  • No.

Optical coatings

• Fully coated (FC).

Mounting

• Dovetail standard:

  • Vixen.

Warranty

• Manufacturer's warranty:

  • 60 months.