Wndsn Sine Quadrant (SqTM) qt90 White Acrylic

Wndsn Sine Quadrant (SqTM) qt90 White Acrylic

Regular price €42.50 Sale

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The Wndsn Sine Quadrant is another companion tool to the Wndsn Quadrant Telemeters and the printed manual, which includes an extensive part on the use of the Sine Quadrant.

The Sine Quadrant is an instrument for the true enthusiast, a mathematical tool to solve trigonometric calculations. The Sine Quadrant features a string that is attached to its vertex and is used to perform calculations by positioning it across the scales, much like the other flagship Telemeters in the Wndsn line of instruments.

The Sine Quadrant is unassuming at first glance, of what merely amounts to graph paper. Unlike the Horary Quadrant which gives away some of its functions on sight or at least hints at its capabilities, the Sine Quadrant is rather opaque, with nary a hint at its powerful functionality. Yet, it is the most elegant of tools. If you don’t know what it is, it appears to be no more than decorative patterns. However, the interaction between the sexagesimal scale and the 90 degree angular scale, allow a range of graphic calculations, from the simple finding of a sine, to the complex, dividing a sine by a cosine in order to determine the bearing of the Sun.

The Wndsn Sine Quadrant has a number of functions:

Measure degrees from vertical or horizontal; determine true vertical; calculate sine and cosine; read declination for a given day; perform graphical computations between angles, trigonometric ratios, and sexagesimal values, along with determining great circle calculations, diurnal arcs, obliquity arcs, hour angles, azimuths, latitude, and determining cardinal directions.

Made in Germany.

  1. Wndsn Sine Quadrant, single-sided
  2. Dyneema string, 0.27 mm turquoise and red, pre-configured in the required lengths
  3. Plumb line weight, tungsten carbide (similar to the one pictured)
  4. Digital 150-page manual (in English, German on request)
  5. Wndsn Sine Quadrant Worksheet Pad

[Note: Due to the manual production process, slight variations in finish can occur.]


  • 6.25" x 6.25" (16 x 16 cm)
  • Matte white surface, black core
  • ~1/8" (3.2 mm) Acrylic stock, laser engraved