Sky-Watcher BKMAK 90 SP Telescope (SW-3001)

The Maksutov optical system is widely appreciated for its portability, ease of use, and versatility. It is an excellent choice for both terrestrial and astronomical observations. Its high-quality optics deliver exceptionally sharp images across a wide field of view. The telescope features a meniscus corrector plate, a primary mirror, and a secondary mirror mounted on the inner surface of the meniscus. This optical design minimizes coma and produces only negligible chromatic aberration, resulting in crisp, high-contrast images. One of the major advantages of Maksutov telescopes is their compact size, short tube length, and relatively low weight. Their long focal length and high focal ratio make them particularly well suited for planetary observation. This design also performs well in urban environments, where bright skies make observing faint deep-sky objects more challenging.

Optical Design

The telescope utilizes a Maksutov-Cassegrain optical system consisting of a spherical meniscus corrector lens made of crown glass, a primary mirror, and a secondary mirror mounted on the inner surface of the corrector. This design significantly reduces coma and astigmatism while keeping chromatic aberration to a minimum. The result is exceptionally sharp and detailed images with excellent contrast.

Thanks to its long focal length and relatively slow focal ratio, this telescope is ideally suited for observing the Moon and planets. However, it is not designed for wide-field viewing and is less suitable for observing large nebulae or other extended deep-sky objects.

The telescope gathers approximately 180 times more light than the fully dark-adapted human eye, allowing observations of celestial objects down to nearly magnitude 11.4 under good observing conditions. Its optical resolution enables the separation of double stars with an angular distance greater than approximately 1.6 arcseconds.

Mount

The telescope is supplied without a mount. The optical tube can be attached directly to a photographic tripod using the integrated mounting connection. A tripod with fine-motion controls is recommended for improved tracking and ease of use.

Focuser

The telescope is equipped with a standard 1.25-inch eyepiece holder. Focusing is achieved using the adjustment knob connected to the primary mirror mechanism, allowing precise image focusing by moving the primary mirror. Two compatible 1.25-inch eyepieces are included with the telescope.

Astronomical Observations

Solar System

• Lunar surface features larger than approximately 2–4 km.

• Sunspots and their structure (with a proper solar filter).

• All major planets of the Solar System.

• Phases of Mercury and Venus.

• The visible disk of Mars.

• Jupiter's equatorial cloud bands and the four Galilean moons.

• Saturn's rings and its brightest moon, Titan.

• Uranus and Neptune.

• Asteroid movement against the background stars.

• Bright comets.

Stars

• Approximately 1.3 million stars across the entire sky, down to about magnitude 11.4.

• Double and multiple star systems separated by more than approximately 1.6 arcseconds.

• The natural colors of the brightest stars.

Deep-Sky Objects

• The brightest objects in the Messier Catalog.

• Dozens of globular clusters.

• Hundreds of open star clusters.

• The brightest nebulae.

• Several of the brightest galaxies.

Terrestrial Observations

The telescope includes a 90° mirror diagonal, which produces a left-right reversed image. For correctly oriented terrestrial viewing, a prism diagonal should be used instead. When combined with a suitable prism diagonal and an alt-azimuth mount or photographic tripod, the telescope performs well for daytime terrestrial observation.

Included Accessories

• 1.25-inch 90° mirror diagonal.

• 1.25-inch Super 20 mm eyepiece.

• 1.25-inch Super 10 mm eyepiece.

• Star Pointer finder scope.

Specifications

• Catalog Number: SW-3001

• Telescope Series: Sky-Watcher SkyMax

• Optical Design: Maksutov-Cassegrain

• Mount Type: Optical tube only (no mount included)

• Aperture: 90 mm

• Focal Length: 1250 mm

• Focal Ratio: f/13.9

• Limiting Stellar Magnitude: 12.4

• Maximum Useful Magnification: 180×

• Rayleigh Resolution: 1.59 arcseconds

• Dawes Resolution: 1.29 arcseconds

• Light Gathering Power: 165×

• Optical Tube Weight: 1.4 kg

• Tube Length: 240 mm

• Tube Diameter: 100 mm

• Focuser Type: SCT/MAK

• Eyepiece Holder Diameter: 1.25 inches

• Fine Focuser: No

• Central Obstruction: 32%

• Mounting Rail: Vixen-style dovetail

• Warranty: 60 months