Tessaro Corrie 70 Maksutov-Cassegrain, tube only

Specifications

Description

The Corrie 70 is a Maksutov-Cassegrain telescope with 70 mm of aperture and 700 mm of focal length, giving a focal ratio of f/10. A thick meniscus corrector plate sits at the front of the tube, and a central aluminized spot on its rear surface reflects light to the primary mirror. The primary sends the light back through a hole in the corrector to the eyepiece. This folded light path keeps the tube short, so the instrument fits in a small bag for travel.

At f/10 the optics produce a narrow field, which suits the Moon, the planets, and close double stars. Magnification depends on the eyepiece: a 10 mm eyepiece gives 70x, and a 25 mm eyepiece gives 28x. The long focal length keeps the field edge sharp with common eyepieces. Because the front of the tube is closed by the corrector, the optics need less collimation than an open reflector. The secondary mirror should still be checked after transport.

The 1.25 in rack-and-pinion focuser holds a star diagonal and eyepieces with a 1.25 in barrel. The 6x30 right-angle finder helps you center targets before you look through the eyepiece. At 1.4 kg for the tube, the Corrie 70 sits well on a small alt-az mount or a tabletop tripod. The thick corrector takes longer to reach outdoor temperature than a refractor of the same aperture, so allow time for it to cool before critical observing.

Typical targets include lunar craters along the terminator, the phases of Venus, the rings of Saturn, and bright double stars such as Castor. Open clusters such as the Pleiades appear at low power in a wide eyepiece. Fainter deep-sky objects are easier to see from dark sites.

About this configuration

The Tessaro Corrie 70 Maksutov-Cassegrain is offered in several configurations, and the notes below describe what this particular combination adds or changes. 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. Matte black paint gives the telescope a low-key look, although a dark tube is harder to find on a moonless night.

A UHC filter from the deep-sky kit darkens the background sky around emission nebulae, especially under suburban light. This is the 2023 edition of the Corrie line, the earliest version that is still listed in the catalog. Check the specifications table for the optical figures, since they stay the same across every configuration of the Corrie line.

What's in the box

• Optical tube with front and rear dust caps
• 1.25 in star diagonal
• 6x30 right-angle finder with bracket
• Dovetail mounting bar
• Instruction manual
• 24 mm wide-field eyepiece (1.25 in)
• UHC nebula filter (1.25 in)

Compatibility notes

• Accepts 1.25 in eyepieces directly in the focuser.
• The dovetail bar fits most small alt-az and equatorial mounts.
• The rear cell accepts a T-thread camera adapter once the diagonal is removed.