Looking for the Wndsn store? This way, please.

Wndsn Quadrant Telemeters

Description and use.

The Wndsn Quadrant Telemeter is a simple observational tool for measuring angles via various inputs combined with a number of means to directly process the acquired values.

Telemeter Uses & Applications

The Quadrant Telemeter is a quite versatile tool.

Who uses our Telemeters and what for?

  • Wilderness explorers who need to determine their position indirectly, using landmarks.
  • Urban explorers charting routes.
  • Emergency and security personnel calculating dispatch and traversal times.
  • Ship navigators for aiding celestial navigation offshore or when close-to-shore, an extra tool to determine a fix on a line of position (LOP).
  • Astronomers to prepare and aid star gazing.
  • Surveyors to create quick working estimates.
  • Hunters assessing range whilst targeting fast moving prey.
  • Snipers calculating shot groupings in training and reliably converting Mil and Moa to distance.
  • Archers, to set up targets at consistent distances.
  • Teachers (and students) demonstrating and visualizing trigonometry.
  • Parents and children, to gain a better understanding of the world through science.

The Quadrant Telemeter lets you measure angular size and compute distance, height or depth of object, altitude, or elevation, it allows computation of sine, cosine, and tangent for a given angle. Here are some of the practical tasks where people make use of Quadrant Telemeters.

Land navigation

  • Determine distance to an object with at least one known dimension.
  • Perform resection trilateration by determining distance to two known landmarks.
  • Perform resection triangulateration by determining distance and shooting a compass bearing to one known landmark.
  • Measure the height of a building, tree, or other feature using a vertical angle and a distance (determined by taping or pacing), using built-in trigonometry.
  • Measure the elevation of a vantage point based on a known height of an arbitrary object.
  • Measure the length of a tunnel, height of a chimney etc.
  • Measure steepness of a ski slope.
  • Set firing angle of a cannon or gun (determines projectile range).

Celestial navigation

  • Find local latitude by measuring angular height of Polaris (in the Northern Hemisphere) or the two stars of the constellation Crux (in the Southern Hemisphere).
  • Using the Quadrant as a star compass.
  • Measure an arbitrary latitude to control travel on a parallel.
  • Perform trilateration.
  • Measure angular distance between two stars.


  • Calculate the depth of water underneath an anchored ship.
  • Indicate pitch and roll of vehicles, nautical craft, and aircraft.
  • Measure the list of a ship in still water and the roll in rough water.


  • Measure the height of objects knowing the distance.
  • Measure the depth of a well.
  • Measure length of objects in cm with the a scale as a ruler.
  • Find a perpendicular by making a plumbline.
  • Showing a deviation from the true vertical or horizontal.
  • Directly measure angles making use of the built-in unit circle and the string.
  • Plan the location and scales of a sun dial.
  • Use the quadrant as protractor.


  • Calibrate the Telemeter's resolution by calculating the smallest object measurable at a given distance.
  • Explore the concept of Turing-completeness in a metrological context.


  • Determine the angle of the earth's magnetic field with respect to the horizontal plane.
  • Measure the altitude of the Sun to calculate the time of day.
  • Setup and use the Quadrant Telemeter as an equatorial sundial.
  • Compute the declination of the Sun for a given day.
  • Compute various data from Sun altitude and declination, like hour angle, daylight hours, cardinal direction of the Sun, etc.
  • Calculate distances with the nomograph from angular sizes measured with devices like scopes, etc.
  • Determine a body's angular size, knowing dimension and distance.
  • Reading and calculating right ascension and hour angle of celestial objects.
  • Reading and calculating culmination times of celestial objects.
  • Calculating duration and start and end times of twilights.


  • Chart terrain around points of interest.
  • Measure an angle of inclination, slope, or incline.
  • Determine the dip of beds or strata, or the slope of an embankment or cutting; a plumb level.
  • Measure the slope angle of a tape or chain during distance measurement.
  • Measure the orientation of planes and lineations in rocks, in combination with a compass, in structural geology.
  • Measure the angles of elevation to, and ultimately computing the altitudes of, many things otherwise inaccessible for direct measurement.
  • Determine the circumference and diameter of the Earth.
  • Calculate any great circle between locations with known coordinates.


  • Demonstrate the slide rule principle of jumping scales by shifting powers of ten.
  • Use the Telemeter like a Kamal by graduating a string based on the diameter of the short side.
  • RFID shielding (Radio-frequency identification uses electromagnetic fields to automatically read tags attached to objects).
  • Visualize obstacle detection in autonomous car navigation.
  • The high-gloss acrylic Quadrant Telemeter can be used as a makeshift nephoscope, to measure speed, and direction of clouds.


  • Calculate sines and cosines of angles.
  • Calculate sines and cosines as ratios.
  • Calculate tangent, cotangent, and 1/tangent.
  • Calculate angles from sines and cosines and tangent.
  • Multiply and divide angles.
  • Visualize the quadrants of the unit circle.


  • Aid finding altitude angle of e.g. Moon eclipses to set up equipment.
  • Plan shadow and light directions for outdoor photo locations.


  • Calculate solar windows for solar panel installation.
  • Adjust a solar panel to the optimal angle to maximize its output.
  • Measure the look angle of a satellite antenna towards a satellite.


  • Suspend under water as fishing lure or decoy device.
  • Reflect sun or artificial light to send distress signals to rescuing parties.
  • Disaster site forensics.

Makeshift medicine

Religious observation and ritual use

  • Determine prayer times in unequal hours.
  • Measure time in unequal hours.
  • Calculate the direction of Mecca; the qibla.

Obscure Telemeter uses

  • Deep space navigation.
  • Aid intergalactic adventures using known ephemerides to calculate position and trajectory.

Shop Wndsn Telemeters