Professional Imo Standard Marine Sextant

• Customization: Available
• Application: Professional Equipment
• Certification: Na
• Model NO.: sextant
• Material: Na
• Suitable for: Adult
• Type: Na
• Using Field: Aquatic
• Color: Black
• Arc Measurement: 60° (1/6 Circle)
• Accuracy: ±0.1' to ±0.2' (Arc Minutes)
• Mirrors: Index Mirror & Horizon Glass
• Telescope: 3X to 6X Magnification
• Filters: Neutral Density (Sun) & Light-Enhancing (Stars)
• Transport Package: Carton
• Specification: SMALL SIZE
• Trademark: MATCHAU
• Origin: Zhenjiang, Jiangsu, China
• HS Code: 9014800000
• Production Capacity: 200 Piece/Pieces Per Month
• Package Size: 37.00cm * 31.00cm * 19.00cm
• Package Gross Weight: 5.000kg

Product Description

Marine Sextant: A Precision Navigation Instrument

The marine sextant is a critical navigational tool used to measure the angle between celestial bodies (such as the sun, moon, planets, or stars) and the horizon. This measurement, known as the altitude, allows mariners to determine their latitude and, with additional calculations, their longitude at sea.

Key Components & Functionality

1. Frame & Arc

   • Typically made of brass, aluminum, or stainless steel for durability in harsh marine environments.

   • Features a 60-degree graduated arc (though it can measure up to 120° due to double reflection).

2. Optical System

   • Index Mirror (movable) - Reflects the celestial body.

   • Horizon Glass (half-mirrored) - Allows simultaneous viewing of the horizon and reflected celestial object.Telescope or Monocular (3x-6x magnification) - Enhances precision when aligning the horizon and celestial body.

3. Filters & Shades

   • Adjustable neutral-density filters protect the observer's eyes when sighting the sun.

   • Clear or light-enhancing filters improve visibility of stars or a dim horizon.

4. Micrometer & Vernier Scale

   • Enables readings with precision up to 0.1 arc minutes (though typical accuracy is ±0.2').

   • Some models feature a drum micrometer for fine adjustments.

How It Works

1. The navigator sights the horizon through the horizon glass.

2. The index arm is adjusted until the reflected celestial body aligns with the horizon.

3. The angle is read from the scale, corrected for index error, dip, and refraction.

4. Using nautical almanac data and the exact time (GMT), the observer calculates their position via celestial navigation.

Advantages Over Modern Systems

No reliance on electronics or GPS - Essential in emergencies or remote areas.
High accuracy when properly used (error <1 nautical mile in skilled hands).
Durable and long-lasting - Requires minimal maintenance.

Modern Usage

While largely replaced by GPS, marine sextants remain:

• Mandatory backup equipment on commercial ships (per IMO regulations).

• Taught in maritime academies as part of traditional navigation training.

• Used by ocean sailors for celestial navigation in long voyages.

Variations & Enhancements

• Periscopic sextants - For use in submarines.

• Bubble sextants - For aviation (when no horizon is visible).

• Digital sextants - Electronic angle measurement (rare, as they defeat the purpose of non-electronic reliability).

  Parameter	Specification	Description
  Arc Measurement	60° (1/6 circle)	Measures angles up to 120° via double reflection.
  Accuracy	±0.1' to ±0.2' (arc minutes)	High-precision models can achieve ~0.1' error.
  Material	Brass, aluminum, or stainless steel	Brass for classic models, aluminum for lightweight, stainless for durability.
  Mirrors	Index mirror & horizon glass	High-quality optical glass with silver coating for reflectivity.
  Telescope	3x to 6x magnification	Adjustable focus for clear horizon/celestial alignment.
  Filters	Neutral density (sun) & light-enhancing (stars)	Protects eyes when observing bright objects like the sun.
  Weight	0.5-2.5 kg (1.1-5.5 lbs)	Lighter models (aluminum) for ease of use.
  Scale Resolution	1' (arc minute) or finer	Vernier scale allows readings up to 0.1' or 0.2'.
  Radius of Arc	15-20 cm (6-8 inches)	Larger radius improves accuracy.
  Damping Mechanism	Oil or spring-based	Stabilizes the index arm for steady readings on moving vessels.
  Certification	IMO standards	Compliant with maritime navigation requirements.

Packaging & Shipping

PACKING DETAILS:

1.ITEMS:

1*Sextant                                                    1*Brush

1*Telescope                                               1*Wipe flannel

1*Adjusting key                                          1*Instruction

1*A bottle of oil                                           1*Certificate of qualification

1*Screw driver

Package

1PCS/CARTON,PACKED BY WOODEN CASE OR ALUMINIUM CASE FIRSTLY.

G.W.:4.6kg     N.W.:3.75kg       Dimension:41*34.5*23.5cm

Delivery time: Within 15 days after order confirmed.
 

Company Information