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Wndsn Quadrant Telemeters

Wndsn Graphical Telemetry Computers: Low tech, high utility distance and altitude nomographs from the Wndsn applied science lab

Wndsn Quadrant Telemeter Tutorials

Making the most out of our graphical telemetry computers.

Like with many complex instruments, there are multiple ways to solve certain problems and to measure the required inputs. Combining the various functions leads to a multitude of advanced uses. See also the printed manual.

Using the Latitude Quadrant as a Star Map

Level: Advanced

Instrument used: Wndsn Latitude Quadrant

Similar (but different) to an Astrolabe, the stars on a Latitude Quadrant can be used as a partial map of the (southern) sky for the designated latitude. By aligning the string with the current date and pointing the resulting line toward south, the stars to the right of the string correspond to the current south-western sky and the stars to the left of the string correspond to the current south-eastern sky.

The Procedure

  1. Find south with a compass
  2. Align the string on the Quadrant with the current date on the calendar scale
  3. Align the vertex of the Quadrant in line with the string toward south
  4. You now have a map of the sky,
    • with the stars around the string culminating around the current date, hence visible around due south,[1]
    • and the stars toward either far side of the string culminating earlier or later in the year, hence visible in the corresponding cardinal direction, right of the string in the west, left of the string in the east.

Notes

  • Positioning of the star labels for the culmination date: Above the star refers to the inner calendar scale (JAN-JUN), and below the star refers to the outer calendar scale (JUL-DEC).
  • The eastern and western boundaries of the star map are determined by the calendar scale (compare the blue highlight on the Quadrant below).

Example

Time: beginning of April (compare the string); latitude: 50° north.

  • Aldebaran (α Tauri) on the right of the Quadrant (culminating at the end of November) is observable in the sky due west.
  • Spica (α Virginis) in the center of the Quadrant (culminating in mid-April) is observable in the sky around due south.
  • Altair (α Aquilae) on the left of the Quadrant (culminating at the end of July) is observable in the sky due east.

Aligning the cardinal directions with the Latitude Quadrant.

Aligning the cardinal directions with the Latitude Quadrant. The string through the vertex points toward south. The blue highlight is the area of the star map.

Wrap Around

The string moves through the Quadrant (and hence through the map of the sky) over the course of a year, corresponding to the rotation of the Earth around the Sun. It follows that for observations around the December solstice, we will have to imagine the Quadrant "wrapping around" itself -- the stars then to the right of the string (west) are starting over on the left of the Quadrant (east). Vice versa for observations around the June solstice, where the calendar[2] wraps around.

Footnotes:

  1. For an explanation on culmination see How to Draw Stars on Your Latitude Quadrant ↩
  2. Using the calendar is shown in determining the RA in How to Draw Stars on Your Latitude Quadrant ↩

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