Introducing the Advanced Astrolabe

For quite some time now I have been basing my class, and my discussions here, on an astrolabe with fairly basic options. Linked to the right you will find a zip file containing the components for this basic astrolabe, along with the handout for my class. But there is more to the astrolabe than just […]

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 […]

An Astrolabe in Work

I got this last night via Twitter: Nice work, he has a steadier hand than I do. Please do email or tweet me your astrolabes, I’ll be glad to post them. Addresses are on the right.  

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 […]

Pennsic War 42 Followup

(Ok, so I’m a bit late with my essay “What I did on My Summer Vacation”, sue me.) I committed to three activities related to this project this past Pennsic: Firstly, I taught a pair of two-hour sessions of my class “The Astrolabe in Theory and Practice” at Pennsic University. In addition I displayed my […]

What I’ve been up to

Wow, how time flies. It is almost a year since I last posted here.  New Years Resolution: Post at least once a week. Yeah, let’s see how long That One lasts… Not that I’ve been idle. In the intervening months I have gotten quite a bit done, I just haven’t been sharing. Since my last […]