Freiberger Drum Sextant

The Freiberger Drum Sextant is a premium, full-size marine instrument designed for accurate celestial navigation aboard deep-sea vessels or during advanced training. Built in Germany to rigorous standards, it offers precision, clarity and durability for serious navigators.

The instrument features a robust light metal alloy frame that is rigid, corrosion-resistant, and well-balanced in hand. The index arm is fully enclosed between the frame and handle, offering excellent protection against spray and dirt. The standard 4x40 telescope is height-adjustable and fitted with a rubber eyepiece for comfortable sight-taking.

Brightness is controlled via swing-in graded filters – four for the index mirror and three for the horizon mirror – ensuring equal luminosity of both images. High-quality optics, tested for flatness and parallelism, provide clear readings in all conditions. The micrometer drum and clamping device are fully enclosed for maximum protection.

This instrument is a dependable navigation system that requires no electronics and is not affected by electromagnetic interference – offering peace of mind on long voyages.

Features

• Used to measure celestial altitude for position fixing at sea or on land
• Fully manual system – independent of electronics or power
• Enclosed micrometer drum for protected angle measurement
• High-quality swing-in filters to adjust image brightness
• Available with split-view or full-view horizon mirrors
• Frame made from lightweight, corrosion-resistant aluminium alloy
• Large visual field with 4x magnification and 40 mm aperture
• Supplied with hardwood handle
• Includes high-quality wooden case, adjustment tool, test certificate, and user’s guide

Technical Data

• Graduated Arc
  Radius: 170 mm
  Scale: −5° to 125° (interval: 1°)
• Drum Graduations
  Interval: 1'
  Visual Estimation: 0.1'
• Telescope
  Aperture: 40 mm
  Magnification: 4x
• Dimensions
  Sextant: 26 × 24 × 13 cm
  Carrying Case: 34 × 32.2 × 17 cm
• Weight
  Sextant: 1.4 kg
  With Carrying Case: 4.5 kg
• Materials
  Frame: Aluminium alloy
  Handle: Hardwood
  Colour: Black

Mirror Options

Split-View Mirror: A reflective right half and non-mirrored left for greater horizon visibility. Ideal for experienced users seeking maximum clarity.

Full-View Mirror: Translucent with full reflective coating. Offers uninterrupted view of celestial body and horizon – recommended for beginners.

About Freiberger

FPM Holding GmbH (Freiberger Präzisionsmechanik) continues a 250-year tradition of fine mechanical and optical instrument making in Freiberg, Germany. Their instruments are used in marine navigation, civil engineering, surveying, and structural monitoring worldwide.