Tessaro Lumen 127 Maksutov-Cassegrain, tube with alt-az mount

Specifications

Description

The Lumen 127 is a Maksutov-Cassegrain telescope with a 127 mm aperture and a 1,500 mm focal length, folded into a tube about 35 cm long. The focal ratio of f/11.8 favors high magnification, which makes the Lumen 127 a good match for the Moon, the planets, and double stars.

A Maksutov uses a thick meniscus corrector at the front and a spherical primary mirror at the back. The secondary mirror is an aluminized spot on the inside of the corrector, so there is no spider and no diffraction spikes on bright stars. The optics are fixed at the factory and rarely need collimation.

With a 10 mm eyepiece the Lumen 127 reaches 150x, and a 6 mm eyepiece gives 250x on nights of steady air. At those magnifications Jupiter shows its belts, festoons, and the shadows of its moons, Saturn shows the Cassini Division, and the Moon shows small craterlets inside larger craters. Close double stars such as Porrima and Izar split cleanly.

The long focal length gives a narrow field. Large objects such as the Pleiades or the Andromeda Galaxy do not fit in the field, so the Lumen 127 is less suited to wide deep-sky views than a short refractor or a Newtonian. Small bright targets such as the Ring Nebula and globular clusters work well.

Focusing moves the primary mirror inside the tube, which gives a long focus range for cameras and diagonals. The thick corrector needs time to cool, about 30 to 45 minutes on a cold night. At 3.5 kg, the tube rides on light mounts and suits apartments and travel.

About this configuration

The Tessaro Lumen 127 Maksutov-Cassegrain is offered in several configurations, and the notes below describe what this particular combination adds or changes. The included alt-az mount moves up and down and side to side, so you point the telescope by hand without polar alignment. Manual alt-az motion suits visual observing, though you need to nudge the tube now and then to follow objects as the sky turns. Gloss white paint is easy to wipe clean, and the tube stays easy to spot in a dark yard.

With the imaging kit, a camera attaches at prime focus, so the telescope works as a long telephoto lens. This is the 2024 edition, which revised the packaging and the accessory fittings of the Lumen line. 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 dust cap
• Vixen-style dovetail bar
• 90-degree star diagonal (1.25 in)
• Red-dot finder
• Alt-az mount with aluminum tripod
• T-ring and T-adapter
• Bahtinov focusing mask

Compatibility notes

• The rear port takes 1.25 in diagonals and eyepieces; a 2 in diagonal needs an adapter for the rear thread.
• The Vixen-style dovetail bar fits most small alt-az and equatorial mounts.
• Planetary cameras attach with a 1.25 in nosepiece or the rear T-thread.