Lanthorn Beacon 20x56 binoculars

Specifications

Description

The Beacon 20x56 is a large astronomy binocular with 56 mm objectives and 20x magnification. The combination gives a true field of 2.8 degrees, an apparent field of about 56 degrees, and an exit pupil of 2.8 mm. That exit pupil suits dark-adapted observers, and it keeps faint nebulae and open clusters bright under suburban skies.

At 20 power, the view is steady enough for hand-held use with your elbows braced against your chest, although a tripod adapter makes longer sessions more comfortable. The Orion Nebula, the Double Cluster in Perseus, and the Beehive Cluster in Cancer each fit within the field. Sweep slowly across the Milky Way in Sagittarius and Scutum, and you can trace star clouds that wider binoculars show only as diffuse haze.

The roof prisms use BaK-4 glass, and the objectives carry multi-layer coatings on the main surfaces. O-ring seals and a nitrogen purge keep the optical path free of internal fogging when you move from a warm room into cold night air. The 16 mm eye relief allows observers who wear glasses to see most of the field, but the rubber eyecups must be fully extended to reach the full view.

At 1,450 g, the Beacon 20x56 is too heavy for comfortable hand-held use over long sessions, so use a tripod, a parallelogram mount, or a reclining chair with the elbows supported. Close focus is 8 m, and the central focus knob turns smoothly through the full range. The right-eye diopter corrects differences between the two eyes and needs to be set only once with a distant object.

Start with the Moon to practice focusing, then move to the clusters in Perseus and Cassiopeia on a moonless night. Record which objects you can find without the star chart, and return to them later to compare how the view changes with transparency and altitude.

About this configuration

The Lanthorn Beacon 20x56 binoculars comes in several configurations, and the notes below explain what this particular combination includes. This package contains the binoculars with their strap, lens caps, and case, without any mounting hardware. Binoculars alone suit hand-held scanning of the Milky Way, bright star clusters, and the phases of the Moon. The multi-coated version suits casual scanning of the night sky as well as daytime nature viewing.

The tan armor is easy to spot when you set the binoculars down on the grass in the dark. The 2023 edition uses the same prisms and objectives as later years, with small differences in the eyecups. The magnification, field, and exit pupil figures in the specifications table apply to every configuration of the Beacon line.

What's in the box

• Binoculars with neck strap
• Objective and eyepiece caps
• Hard carrying case
• Lens cleaning cloth

Compatibility notes

• The central tripod socket takes a standard L-shaped binocular adapter with a 1/4-20 thread.
• Fits parallelogram mounts and binocular harnesses rated for 1.5 kg binoculars.