Corvane Gannet 127 catadioptric, tube only

Specifications

Description

The Gannet 127 is a Schmidt-Cassegrain catadioptric telescope with 127 mm of aperture and 1270 mm of focal length, giving an f/10 focal ratio. Light enters through a thin corrector plate, reflects from a spherical primary mirror to a secondary mirror mounted on the plate, and passes back through a hole in the primary to the eyepiece. This folded path packs a long focal length into a compact tube.

At f/10 the Gannet 127 gives high magnification on the Moon, the planets, and close double stars, while a 25 mm eyepiece still yields a field wide enough to frame larger planetary nebulae. The corrector plate and secondary mirror produce a central obstruction, so planetary detail shows slightly less contrast than it would in an unobstructed reflector of the same aperture. The tube is baffled and the optics are coated to keep contrast steady on lunar work. Expect the thick corrector plate to take time to reach outdoor temperature, so set the telescope out before your session begins.

The focuser is a 1.25 in rack-and-pinion unit, and it accepts a star diagonal for overhead viewing. The 6x30 right-angle finder gives a wide field for star hopping before you switch to the eyepiece. At 6.2 kg for the tube, the Gannet 127 needs a sturdy equatorial or alt-az mount with a payload rating of at least 8 kg, so check the mount's load rating before you buy. Under dark skies, typical targets include the craters along the lunar terminator, the rings of Saturn, the cloud bands of Jupiter, and bright planetary nebulae such as the Ring Nebula in Lyra.

About this configuration

The Corvane Gannet 127 catadioptric 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. Gloss white paint is easy to wipe clean, and the tube stays easy to spot in a dark yard.

With the starter kit, begin with the low-power eyepiece whenever you search for a new target, then switch up. The 2023 edition uses the same optical design as later years, with small differences in fittings and labels. Check the specifications table for the optical figures, since they stay the same across every configuration of the Gannet line.

What's in the box

• Optical tube with corrector plate
• Tube rings with dovetail bar
• 1.25 in star diagonal
• 6x30 right-angle finder
• Front and rear dust caps
• 25 mm and 10 mm eyepieces (1.25 in)
• 2x Barlow lens (1.25 in)

Compatibility notes

• Accepts 1.25 in eyepieces through the rear focuser and the supplied diagonal.
• The included dovetail bar fits standard small and medium mounts.
• 2 in eyepieces require an optional reducer and are not supplied.