Refractortelescoop Skywatcher BK 709 EQ1 70 mm opening 900 mm brandpuntsafstand

The Skywatcher BK 709 EQ1 is a refractor telescope with a 70 mm clear aperture and a 900 mm focal length mounted on an EQ1 equatorial tripod. It is designed for visual observation of the Moon, planets and brighter deep-sky objects, and also supports terrestrial viewing. The optical design and moderate focal length offer a balance between wide-field views and sufficient magnification for planetary detail. The included EQ1 equatorial mount provides manual tracking capability for simple follow-up of celestial motion, making the instrument suitable for beginners and for introductory astrophotography with small cameras.

Advantages

The 70 mm objective delivers good light gathering for a compact refractor, producing clear images of the Moon and planets and enabling views of brighter nebulae and star clusters. The 900 mm focal length yields a focal ratio that helps reduce chromatic aberration typical for achromatic refractors while providing usable magnification with a range of eyepieces. The EQ1 equatorial mount allows polar-aligned manual tracking, improving ease of use during observation sessions and allowing simple long-exposure tests when paired with a lightweight camera or smartphone adapter. The overall package is lightweight and portable, suitable for transport to observing sites and for storage in limited spaces.

Suitable for

• Beginner visual astronomy: Moon and planetary observation
• Terrestrial viewing and distant landscape observation
• Observation of brighter deep-sky objects such as open clusters and some nebulae
• Introductory astrophotography with small cameras or smartphone adapters

Key specifications

• Optical type: refractor (achromatic)
• Aperture: 70 mm
• Focal length: 900 mm
• Mount type: EQ1 equatorial mount with manual slow-motion controls
• Typical use: visual observation and basic imaging
• Portability: compact and lightweight design for easy transport

How to use

Set up the telescope on a level surface and assemble the optical tube onto the EQ1 equatorial mount following the supplied mounting points. Roughly align the mount's polar axis toward the celestial pole for improved manual tracking; in northern latitudes this means pointing toward Polaris. Install an appropriate eyepiece to start with a low-power view, focus using the focuser knob, then switch to higher magnification eyepieces as seeing conditions allow. For terrestrial viewing, avoid pointing directly at very bright reflective surfaces and allow the instrument to thermally acclimate for sharper images. For basic astrophotography, attach a lightweight camera or smartphone adapter and make short test exposures while using the mount's slow-motion controls to keep the target centered.

Recommendations

Use low- to medium-power eyepieces for initial framing and targeting, then increase magnification for planetary detail if atmospheric seeing is steady. Perform a rough polar alignment of the EQ1 mount to reduce drift during observation. Protect optics from dew with a dew shield or heater in humid conditions, and store the telescope in a dry place to preserve coatings and mechanical parts. When attempting long-exposure imaging, keep exposures short and test balance on the mount to avoid excessive strain on the manual drive.