Tessaro Lumen 72 Maksutov-Cassegrain, tube only

Specifications

Description

The Lumen 72 Maksutov-Cassegrain is a catadioptric telescope built around a 72 mm meniscus corrector and a spherical primary mirror. With 864 mm of focal length, it works at f/12, a slow ratio that gives high magnification on the Moon and the planets from a short, compact tube. The sealed optical tube keeps dust off the corrector and mirror between sessions, and it limits the air currents that can drift across the optics while you observe.

Light passes through the corrector, reflects off the primary mirror back toward a secondary mirror on the corrector, and exits through a hole in the primary. Because the design relies on mirrors and a single corrector, bright planets such as Jupiter and Venus show little or no color fringe. The corrector is prone to slight dew on cool nights, so the dew shield should stay attached during the session. Under good seeing, the optics resolve fine detail on the lunar limb and on the Martian surface when the planet is near opposition.

The 1.25 in rack-and-pinion focuser accepts standard eyepieces and a star diagonal, and a 6x30 finder with a bracket shows the field before you center the target. The tube weighs 1.6 kg, so it sits well on a small alt-az or GoTo mount and carries easily in a backpack. Typical targets include lunar craters along the terminator, the rings of Saturn, and the Ring Nebula in Lyra. The narrow true field means large objects such as the Pleiades need a low-power eyepiece to fit in view.

Because the corrector is thick and the tube is sealed, the optics take longer to reach outdoor temperature than those of a small refractor, so carry the telescope outside about thirty minutes before you observe. Check the alignment of the secondary mirror before each session, since a slightly off-center secondary softens star images across the field.

About this configuration

This listing covers one specific configuration of the Tessaro Lumen 72 Maksutov-Cassegrain, defined by its bundle, finish, accessory kit, and edition year. This is the optical tube on its own, so you need to supply a mount that can carry its weight steadily. Buying the tube alone makes sense if you already own a suitable mount or plan to choose one separately. The gloss white tube reflects sunlight, which helps it stay closer to air temperature while you set up before dusk.

The planetary kit adds a short focal length eyepiece and a set of color filters for the Moon and the bright planets. The 2023 edition uses the same optical design as later years, with small differences in fittings and labels. The optical figures in the specifications table apply to this configuration and to every other version of the Tessaro Lumen 72 Maksutov-Cassegrain.

What's in the box

• Optical tube with dew shield
• Dovetail bar
• 1.25 in star diagonal
• 6x30 finder with bracket
• Front and rear dust caps
• 6 mm planetary eyepiece (1.25 in)
• Four color filters (1.25 in)

Compatibility notes

• Accepts 1.25 in eyepieces and star diagonals directly in the focuser.
• The dovetail bar fits most small alt-az and GoTo mounts.
• A 1.25 in camera adapter can be fitted once the star diagonal is removed.