Varrow Brindle 100 refractor, tube with GoTo mount

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

This listing covers one specific configuration of the Varrow Brindle 100 refractor, defined by its bundle, finish, accessory kit, and edition year. Motorized tracking on the GoTo mount keeps objects in view, which helps when several people take turns at the eyepiece. The GoTo mount needs a 12 V power source, so plan for a power pack when you observe away from a mains outlet. The matte black finish hides scuffs and keeps reflections from porch lights and streetlights to a minimum.

Color filters from the planetary kit can bring out surface markings on Mars and the cloud belts of Jupiter. This is the 2023 edition of the Brindle 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 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
• GoTo mount with steel tripod
• Hand controller and 12 V power cable
• 6 mm planetary eyepiece (1.25 in)
• Four color filters (1.25 in)

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.