Corvane Talus 70 refractor, tube only

Specifications

Description

The Talus 70 is a small achromatic refractor intended as a first telescope. Its 70 mm objective has a focal length of 700 mm, which gives a focal ratio of f/10. That slow ratio keeps the color fringe of a simple doublet low, so the Moon and bright planets look clean at the magnifications this aperture supports.

A refractor needs no collimation, so the Talus 70 is ready to use as soon as you take it outside. The sealed tube keeps dust off the optics, and the lens cools to the outdoor temperature within a few minutes. The 1.25 in rack-and-pinion focuser is simple and smooth enough for the 25 mm and 10 mm eyepieces that most beginners start with.

Through a 70 mm telescope you can see the craters and mountain ranges of the Moon, the phases of Venus, the four bright moons of Jupiter and its two main cloud belts, and the rings of Saturn. Bright star clusters such as the Pleiades and the Beehive look good at low power, and the Orion Nebula shows its brighter core on winter evenings.

The tube weighs 1.9 kg, so a light photo tripod with a sturdy head can carry it for low-power views, while the alt-az bundle gives smoother motion at higher magnification. The focal length also makes the Talus 70 useful during the day for distant landscapes when you add a correct-image diagonal.

The useful magnification limit for 70 mm of aperture is around 140x on a steady night. In practice, most views look best between 30x and 100x. A Barlow lens doubles the magnification of each eyepiece and gives you more steps in that range without extra eyepieces.

About this configuration

This listing covers one specific configuration of the Corvane Talus 70 refractor, 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. Without a mount in the package, check the tube weight against the payload rating of your mount, with some margin to spare. Matte black paint gives the telescope a low-key look, although a dark tube is harder to find on a moonless night.

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 Talus line. Check the specifications table for the optical figures, since they stay the same across every configuration of the Talus line.

What's in the box

• Optical tube with dew shield
• Mounting bracket with 1/4-20 thread and Vixen-style foot
• 90-degree star diagonal (1.25 in)
• Red-dot finder
• Dust caps
• T-ring and T-adapter
• Bahtinov focusing mask

Compatibility notes

• Accepts standard 1.25 in eyepieces and filters.
• The mounting foot fits photo tripods with a 1/4-20 thread and Vixen-style saddles.
• Prime-focus imaging needs a 1.25 in T-adapter and a T-ring for your camera.