Lanthorn Penumbra 20x56 binoculars, with parallelogram mount

Specifications

Description

The Penumbra 20x56 is a large-aperture binocular for observers who want high magnification with a steady view. Its 56 mm objectives gather enough light to show faint deep-sky objects, and 20x magnification brings the Orion Nebula, the Andromeda Galaxy, and open clusters such as M44 and M35 into clear detail. The true field of 2.4 degrees gives an apparent field of about 48 degrees, so you can scan across star clouds in Sagittarius and Scutum without losing your place.

The exit pupil is 2.8 mm, which suits a dark sky and a fully dark-adapted eye. At 20x, small hand tremors show as image movement, so the 1.9 kg total weight calls for support. Mount the binoculars on a parallelogram harness or a tripod adapter, or rest your elbows on a car roof or a sturdy wall. The central focus wheel moves smoothly, and the right-eye diopter corrects for focus differences between your eyes.

The BaK-4 roof prisms are fully multi-coated, which keeps the image bright and the color neutral toward the edge of the field. Nitrogen purging and O-ring seals resist fogging and moisture, so you can use the binoculars on cold, damp nights. The 16 mm eye relief lets observers who wear glasses see most of the field, though the eyecups should be fully extended. The 10 m close focus lets you check focus on nearby daytime targets before dark.

Begin with the Moon a few days after new, when the terminator shows craters in fine relief. Then sweep along the Milky Way from Cygnus toward Scutum, noting the Dumbbell Nebula in Vulpecula and M11 in Scutum. Return to the same objects on a moonless night to compare how much dark skies change the view. Keep a log of each object, its magnification, and the sky conditions, so the notes help you plan later sessions.

About this configuration

All configurations of the Lanthorn Penumbra 20x56 binoculars share the same magnification and objective size; the options below change the package and finish. The parallelogram mount keeps the binoculars at eye level while you move them across the sky in smooth arcs. A parallelogram mount lets observers of different heights share the same view without aiming the binoculars again. The ED version adds low-dispersion glass and full multi-coating for sharper star images toward the edge of the field.

The tan armor is easy to spot when you set the binoculars down on the grass in the dark. The 2026 edition carries the optics over unchanged and updates small parts such as the caps and the case. Compare the exit pupil in the specifications with your sky conditions and your age, since both affect how bright the view looks.

What's in the box

• Binoculars with neck strap
• Objective and eyepiece caps
• Padded carrying case
• Lens cleaning cloth
• Parallelogram mount with counterweight
• Tripod adapter

Compatibility notes

• The central tripod socket takes a standard L-shaped binocular adapter with a 1/4-20 thread.
• Fits parallelogram harnesses rated for 2 kg binoculars.