Astrocompass

A sun compass used to determine the compass direction without the help of the geomagnetic field. He is superior to the magnetic compass there, where this fails, especially in the polar regions.

• 3.1 Middle Ages
• 3.2 Modern Times

Construction

Main design feature of sun compasses is a circular Peilscheibe. This bears on the edge towards brands, similar to the compass rose, as well as several curves on the surface. In the middle is a gnomon, a pointed cone or rod.

Were manufactured devices mainly made ​​of wood, sometimes of metal.

Function

Principle

The plate aligned in the sunlight, the shadow of the course of the Gnomonspitze can be marked on the surface of the Peilscheibe during the daily schedule. Because of the varying with the seasons sun paths and different latitudes, there are various curves. The curves are time markers.

At the point where the distance between the intended curve and Gnomon is shortest, is the north direction.

Application

To determine the compass, the disc is positioned horizontally in the incident sunlight and rotated until the tip of the shadow touches the fit curve to the right timestamp. Now shows the attached North marker to the north.

If the disk is aligned with the aid of the curve to the north, showing the tip of the shadow ( just like with a sundial ) the time of day.

Use

Middle Ages

In 1948, a semi-circular wooden disc ( fragment ) was from the period with a diameter of seven centimeters, found in 1200 in Greenland, which has at its outer edge notches and in the middle part of a hole. CV Solver has interpreted this wood fragment as Peilscheibe. and a number of publications have followed him in this. In the middle is a shadow pin 've found, and from the azimuth of the sun and the shadow of the pin you have to determine the north direction. The contrary held that the notches are carved irregularly on the edge, even though you have precise carving long dominated, ie the quadrant eight, the other nine notches, so that on full circle more than the assumed 32 scores would have to be found. In addition, the disc for this purpose is much too small. In addition, one would have also required amplitude tables and calendars. One can assign the boards no function, and so the imagination are no limits. The arguments against the interpretation as Peilscheibe likely to predominate.

Another tool to determine the position of the sun in cloudy weather, to have been the legendary sólarsteinn ( Sunstone ).

Modern Times

Since the normal magnetic compass in jet fighter aircraft, such as the Me 262, produces distractions and clear error by high field strengths was constructed a sun compass of the navigation instrument company C. Plath Hamburg, which based on a 24-hour automated clock operates. This was used in the Second World War by the Luftwaffe, and in vehicles of the Africa Corps.