Cassens & Plath Sextant POLARIS Clear-view mirror

‌The POLARIS shows its full strength when observing fixed stars and planets.

You can choose between a rough case and a wooden case. You can also have your sextant engraved with your name on request.

Please note: The artificial horizon does not fit into the rough case together with the sextant. Here we recommend the wooden case, in which an additional holder is attached.

Sextant frame and construction

The frame is made from a 5.5 kg brass plate, which is milled to produce a frame weighing approx. 0.6 kg. Once the milling work is complete, the frame is heated in a furnace, straightened, ground and engraved. The individual components are then assembled. Once manufactured, the sextant consists of over 100 individual parts, most of which are produced in-house. All components are assembled and adjusted by hand. Each sextant is tested after manufacture and a quality certificate is issued.

Clear-view mirror

The sextant is equipped with a clear-view mirror. This was developed by Cassens & Plath and features a special design: the central vertical part of the clear-view mirror is half-silvered and therefore semi-transparent, while the side edges are not mirrored and offer an unobstructed view of the horizon. This means that the side areas provide an unobstructed and unobscured view of the horizon, while the centre zone allows both the celestial body and the horizon to be seen at the same time. This has the advantage that, in good light conditions at sea, both day and night, optimal observation conditions prevail and the celestial body can be kept in view more easily, even in rough seas. This simplifies measurement. The clear view mirror thus combines the advantages of the split-view and full-view mirrors without any of their respective disadvantages.

Star spreader

The star spreader is fitted as standard on the POLARIS sextant and can be retrofitted to our other sextant models (except CPSailing). It is located behind the shadow glasses in the index direction and can be used with all horizon mirrors. However, the star spreader cannot be used in conjunction with the student double prism.

As the name suggests, the glass spreads the light point of a celestial body (stars and planets) into a horizontal line. This has two advantages when observing celestial bodies: on the one hand, it simplifies observation, as a horizontal line is easier to align with the horizon; on the other hand, any tilt of the sextant can be clearly seen. This simplifies measurement and increases accuracy.