Refractor Optical Tube Skywatcher BKED 120 OTA, 120mm aperture, 1000mm focal length

The Skywatcher BKED 120 OTA is a 120 mm aperture refractor optical tube with a 1000 mm focal length, engineered for visual observation and astrophotography when used with compatible mounts and imaging equipment. The BKED (Boron-Krypton ED) lens assembly reduces chromatic aberration and improves color correction compared with standard achromats, yielding sharper views of the Moon, planets and wide-field deep-sky targets. The tube’s focal ratio and aperture make it suitable for both high-contrast planetary work and moderate focal-length deep-sky imaging, while its relatively compact dimensions support portable setups and field use.

Advantages

The BKED optical design provides enhanced color fidelity and reduced false color around bright objects, which helps deliver clearer planetary details and more natural star colors in astrophotography. A 120 mm aperture gathers substantial light for resolving finer features and improving contrast on faint nebulae and star clusters. The 1000 mm focal length gives a versatile focal ratio for a range of imaging cameras and eyepieces, balancing magnification and field of view. The OTA’s construction supports easy integration with common mounts and accessories used in amateur astronomy.

Suitable for

• Lunar and planetary visual observation and imaging
• Wide-field deep-sky imaging of nebulae and star clusters
• Portable or backyard observing sessions
• Use with medium-format DSLR or dedicated astronomy cameras

Key specifications

• Aperture: 120 mm
• Focal length: 1000 mm
• Optical type: Refractor with BKED (Boron-Krypton ED) objective
• Focal ratio: f/8.3 (approximate)
• Suitable for visual and astrophotography use
• Compact tube design for portable setups

How to use

Mount the OTA on a stable equatorial or alt-azimuth mount with sufficient payload capacity and balance the assembly before use. Attach a compatible diagonal and eyepiece for visual observing or remove the diagonal and fit a T-ring and camera adapter for imaging. Perform careful collimation and focus using a Bahtinov mask or live-view focusing tools when capturing photographs. For astrophotography, use a guided tracking solution or autoguider and calibrate exposures with flats, darks and bias frames as appropriate for your camera and targets.

Recommendations

For best results, pair the BKED 120 OTA with a stable equatorial mount rated above the combined weight of the tube and imaging accessories, and choose cameras and eyepieces matched to the 1000 mm focal length to achieve the desired image scale. When observing planets, use higher magnification eyepieces under good seeing; for deep-sky targets, use lower focal-reduction or focal-length-matching setups and ensure accurate polar alignment for long exposures.