One of the problems with learning to use an astrolabe is that in order to work through the class notes the student needs to first print out and assemble their own astrolabe from the provided materials. This takes time and materials that may not be ready to hand. What I’ve wanted to do for a […]

Advanced Astrolabe Functions: Estimating the direction to Mecca.

Given that the math and sciences of the Middle East were a major driving force in the development of the astrolabe[1], it is reasonable that some of the advanced functions are related to the dominant religion of the area, Islam. Today we will discuss using two of the astrolabe’s advanced features to estimate the direction […]

Deconstructing the Sine Quadrant-Part 6: Summary and sources

Links The previous installments in this series can be found here: Part One Part Two Part Three Part Four Part Five Printable example Sine Quadrant In the last 5 installments we have broken down the various parts and functions of the sine quadrant. I’ve now come to the end of what I currently know. So […]

Deconstructing the Sine Quadrant-Part 5: The specialized lines – Continued

In part four we examined the Asr lines and how to use them to find the proper times for the start and end of the Asr prayer required of all Moslems. This week we are going to look at an alternate method of determining that by examining yet another of the sine quadrant’s advanced functions. Links […]

Deconstructing the Sine Quadrant-Part 4: The specialized lines – Continued

In Part Three we examined the obliqity arc and how to use it to find the local angle of the Sun at Noon. This week we are going to look at one use for that information, and in doing so, examine another of the sine quadrant’s advanced functions. Links The previous installments in this series can […]

Deconstructing the Sine Quadrant-Part 3: The Advanced Functions Continued

In part two we began examining the functionality provided by the various lines and arcs visible on the front of a typical sine quadrant. The use of the sine and cosine arcs was fairly straight-forward, being related to the basic function of the device (converting from angle to sine/cosine and back). Next we are going to […]

Deconstructing the Sine Quadrant-Part 2: The Advanced Functions

In the previous post, I described the basic features of the Sine Quadrant, and described two of its most common functions: measuring angles and converting back and forth from angle to sine/cosine. [If you need it, here is a link to the PDF of the example sine quadrant you can print out to follow along.] In […]

Deconstructing the Sine Quadrant-Part 1: Introduction

The development of mathematics and the sciences through-out the medieval period spawned a range of clever, elegant tools for observation and computation. Devices such as the Armillary Sphere and the Astrolabe are familiar sights in the art of both Europe and the Middle East; but lesser known are a class of tools known as quadrants. Quadrants come […]