The sine quadrant or Rub'ul mujayyab, allows the user to perform quick, accurate trigonometric calculations; along with several other related functions.
It first appeared in the Middle East and Persia prior to the 10th century, and spread into Europe.
- 3/8 Inch or similar wood, a pale wood by preference. I used craft plywood for this project.
- A bead that fits snugly on the cord, but can be moved as needed
- A weight for the end of the cord, I used a brass fishing weight
For printing on paper: ZodiacSineQuadrant_Print.eps, ZodiacSineQuadrant_Print.pdf, ZodiacSineQuadrant_Print.png
For laser cutting: ZodiacSineQuadrant_Laser.dxf, ZodiacSineQuadrant_Laser.svg
The laser files are colored as follows:
RED: Cut through the material
BLUE, GREEN, YELLOW, PURPLE, BLUE-GREEN: Cut/etch surface. Adjust speed/power to get the best result, the blue-green crosses work best on a lower power than the rest.
BLACK: Raster scan
I covered the top on the wood with painters tape to cut down on smoke residue, then after cutting, used a paint scraper to remove the tape. I cleaned up with an orbital sander.
Drill a small hole at the origin for the cord.
My blog: http://www.astrolabeproject.com/
Class handout: http://astrolabeproject.com/downloads/quadrants/SineQuadrantHandoutVersion1.pdf