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

Every configuration of the Tessaro Lumen 72 Maksutov-Cassegrain shares the same optics; the choices below change how the telescope is mounted, finished, and equipped. This is the optical tube on its own, so you need to supply a mount that can carry its weight steadily. Without a mount in the package, check the tube weight against the payload rating of your mount, with some margin to spare. The matte black finish hides scuffs and keeps reflections from porch lights and streetlights to a minimum.

No accessory kit is included, which suits observers who already own eyepieces and want to reuse them. The optics in the 2024 edition match the other years; the changes concern hardware details only. If you plan to add accessories later, compare the compatibility notes with the parts you already own before choosing a configuration.

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

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.