Varrow Brindle 100 refractor, tube only

Specifications

Description

The Brindle 100 is an achromatic doublet refractor with a 100 mm objective and 800 mm of focal length, which gives a focal ratio of f/8. A ratio this slow limits color fringing on bright objects compared with faster achromats, and it provides a narrower field that suits high-power views of the Moon, the planets, and close double stars. Both lens surfaces carry anti-reflection coating, which raises light transmission compared with uncoated glass of the same size.

The optical tube has a retractable dew shield and internal baffles that reduce stray light reaching the eyepiece. At 3.2 kg for the tube, the Brindle 100 suits a light alt-az mount or a small equatorial mount, and it is light enough to carry outdoors in one trip. The 2 in rack-and-pinion focuser holds a star diagonal and a moderate-weight eyepiece without slipping. Because the focuser has a single speed, fine adjustments at high power take patience, so a steady mount and a low-power eyepiece for initial focusing help considerably.

Typical targets include the Moon, with its craters visible along the terminator, and Jupiter, where the cloud bands and the four Galilean moons are visible in most conditions. Saturn's rings show clearly at moderate power, and Albireo separates into a gold and a blue component at high magnification. Wide-field eyepieces at low power frame the Double Cluster in Perseus, and under dark skies the brighter open clusters in Auriga and Cassiopeia also fit comfortably in the field. Faint galaxies and nebulae are beyond the reach of this aperture from light-polluted sites, so you can expect more detail from rural locations.

About this configuration

Every configuration of the Varrow Brindle 100 refractor shares the same optics; the choices below change how the telescope is mounted, finished, and equipped. 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. A matte white finish reduces glare from nearby lights while keeping the tube easy to see at night.

This configuration comes without extra accessories, so budget for at least one more eyepiece if you are starting out. The optics in the 2024 edition match the other years; the changes concern hardware details only. Check the specifications table for the optical figures, since they stay the same across every configuration of the Brindle line.

What's in the box

• Optical tube with retractable dew shield
• Tube rings with dovetail bar
• 2 in star diagonal with 1.25 in adapter
• Red-dot finder
• Front and rear dust caps

Compatibility notes

• Accepts 2 in eyepieces directly and 1.25 in eyepieces through the supplied adapter.
• The dovetail bar fits most small and medium mounts.
• The focuser has a T2 thread for camera adapters once the 2 in nosepiece is removed.