Tessaro Granite 125 ED refractor, tube with equatorial mount

Specifications

Description

The Granite 125 ED is a doublet refractor with one extra-low-dispersion element in its objective. With 125 mm of aperture and 900 mm of focal length, it works at f/7.2. At low power the field is moderately wide, and at high power the instrument reaches detail on the Moon and planets with less color fringing on bright limbs than an achromatic doublet of the same size and ratio would show.

The objective is fully multi-coated. The tube has several internal baffles, and the retractable dew shield limits stray light from nearby streetlights and windows. When you observe Saturn, the rings and the division between them are visible at moderate magnification, and on the Moon the terminator stays well defined at high power.

The 2.5 in dual-speed rack-and-pinion focuser holds a star diagonal and a heavy eyepiece without slipping. The fine-focus knob gives a 10:1 reduction for planetary detail. The tube weighs 6.8 kg, so you will need a medium equatorial mount or a sturdy alt-az mount rated for the tube plus accessories. Allow the tube to reach outdoor temperature before you attempt high-power planetary work, since a larger refractor takes longer to settle than a small one.

Typical targets include double stars such as Albireo and Epsilon Lyrae, and bright open clusters such as the Pleiades, which fill a 2 in wide-field eyepiece at low power. Under dark skies, brighter planetary nebulae show clear shapes, while galaxies such as M81 and M82 appear as faint elongated patches that benefit from a dark site and a low-power eyepiece.

About this configuration

The Tessaro Granite 125 ED refractor is offered in several configurations, and the notes below describe what this particular combination adds or changes. The equatorial mount follows the sky along one axis once you align its polar axis with the celestial pole. Balancing the tube and the counterweight before each session helps the equatorial mount move smoothly in both axes. The carbon fiber tube expands less as the temperature drops, so the focus point drifts less as the night cools.

The deep-sky kit adds a wide-field eyepiece and a UHC filter for emission nebulae such as the Lagoon and the Orion Nebula. This is the 2026 edition, the most recent version of the Granite line in the catalog. Check the specifications table for the optical figures, since they stay the same across every configuration of the Granite line.

What's in the box

• Optical tube with retractable dew shield
• Tube rings with Vixen-style dovetail bar
• 2.5 in star diagonal
• 8x50 right-angle finder
• Front and rear dust caps
• Equatorial mount with steel tripod
• Counterweight and counterweight shaft
• 24 mm wide-field eyepiece (1.25 in)
• UHC nebula filter (1.25 in)

Compatibility notes

• Accepts 2.5 in eyepieces directly and 2 in or 1.25 in eyepieces through the supplied adapters.
• The Vixen-style dovetail bar fits medium equatorial and alt-az mounts rated for at least 7 kg.
• The focuser has a T2 thread for camera adapters once the 2.5 in nosepiece is removed.