Janus is proud to announce publication of The Astrolabe.

The astrolabe was the most popular and useful astronomical instrument from its introduction in the ancient world through the Renaissance. No device has ever matched the astrolabe's intuitive presentation of the sky and value for solving astronomical problems without calculation. An astrolabe is as an astronomical computer, an observation instrument, a star finder, a handy reference of celestial positions and a tool for astronomy education. Its rich history flows from Greek Antiquity through the Islamic world and into Medieval and Renaissance Europe.
The Astrolabe (Soft cover, 438 pp.) is the most complete astrolabe treatise available. It includes the description, history, use, theory and design of all types of astrolabes and several related devices, updated to modern methods and terminology. Application of computers to astrolabe design and practical advice on making an inexpensive working astrolabe are included.
The Astrolabe is an invaluable reference for anyone with an interest in the history of science and astronomy, the use and history of scientific instruments and, of course, astrolabes. It is an introduction to pre-telescopic instruments for the novice, a reference for teachers and professionals, a guide for designing reproductions and a source for researchers.
The Astrolabe is not a book about specific instruments. It covers the principles and design details of each instrument type. A few pictures of old instruments are included, but only to show how the principles are applied. There are many sources of pictures of historical instruments in books and on the web.
See below for ordering information.
OVERVIEW
The intent of The Astrolabe is to be clear, accurate and complete. Each topic is introduced in very basic terms and expanded with technical details as needed for more sophisticated subjects and applications. A summary of the latest historical research for each instrument and type of instrument is included.
Astrolabes
are visual instruments and are best learned with a visual reference. There
are more than 250 figures showing the details of each instrument and scale
discussed.
The material on applications of computers to astrolabe design is unique. Most of the figures are computer produced and serve as examples of modern astrolabe design.
Also included are figures of the astrolabe components that can be copied and made into a working instrument.
If you like, you can download a PDF of a sample chapter. This chapter covers Gunter's Quadrant and illustrates the level of the overall content, the topics covered and the type of figures included. Keep in mind that the material in this chapter uses terms and ideas covered earlier in the book. Juergen Giesen used this sample chapter to create a unique interactive Gunter's Quadrant at http://www.GeoAstro.de/gunter/.
FAQ
What is unique about The Astrolabe?
- It is the only astrolabe treatise to cover the design of all types of astrolabes completely.
- It contains the first complete discussion of astrolabe related quadrants in modern terms.
- It is the first publication that covers the differences between European and Islamic astrolabes in detail.
- It is the only book that describes how to make astrolabes for southern latitudes.
- It is the first publication to discuss the application of computers to astrolabe design and making a reproduction.
- It is the first astrolabe treatise to include both analytic and graphical methods for designing astrolabe related instruments and the only source having derivations of the layout equations.
What background is needed to understand The Astrolabe?
The astrolabe is an astronomical instrument, so a basic understanding of astronomy terms, such as declination, is helpful but not strictly required as the needed definitions are included. The mathematics of astrolabes is covered at the level of high school trigonometry, with a little basic analytic geometry (such as the equation of a circle). The math is included because it is needed to design an astrolabe. The math can be skipped if you don't want to make an instrument and returned to when needed. The computer related material ranges from very basic to some rather sophisticated programming examples. This material is intended to be useful to anyone who wants to design an astrolabe on a computer. Just ignore it if you don't.
Who are the intended readers?
Based on my experience with The Personal Astrolabe, most readers will be ordinary educated people with an interest in astronomy and its history who have become interested in non-telescopic instruments, such as sundials. I cannot describe a "typical" user of The Personal Astrolabe. Some have technical backgrounds. Many don't. As one might suspect, it is popular with amateur astronomers, medieval recreationists, planetariums and astronomy students. Many sailors have an interest in celestial navigation, which draws them to the old instruments. It seems to be particularly popular with physicians and many users have sailing and/or amateur radio as hobbies. My best guess is that such people just like gadgets, and few gadgets are more engrossing than astrolabes.
Another audience is teachers, particularly those who teach science, medieval history, basic astronomy and the history of science and need reference material in their personal libraries. Clearly, students of the history of astronomy should be familiar with the contents. I assume most scholars are familiar with much of the material, but they may find The Astrolabe to be a useful reference.
Comments from reviewers
Dr. Bruce Stephenson, Curator, Webster Institute for the History of Astronomy, Adler Planetarium & Astronomy Museum
Jim Morrison's wonderful book explains everything that can be said about the astrolabe and related instruments, including all the details of their construction and use. It is animated throughout by a cheerful faith that this preeminent tool of astronomers past can still play a role in 21st-century scientific education and practical life. If you have ever wondered "how an astrolabe works" (at any level of detail), this is the book that will tell you.
Dr. François Charette, historian of Islamic science and author of Mathematical instrumentation in fourteenth-century Egypt and Syria (Brill: 2007).
In The Astrolabe, Jim Morrison treats the noblest instrument of ancient and medieval astronomy with an enthusiasm and respect that is on a par with that of the great medieval scholars who wrote exhaustive treatises on its construction and use. There is no comparable book in the English language. It will be of interest to enthusiast laypersons, but I am also certain students and historians of pre- and early-modern astronomy will enjoy it as well.
John Lamprey - author of Hartmann's Practika (2002), and co-author of Stoeffler's Elucidatio (2007).
The Astrolabe by Jim Morrison promises to be THE STANDARD on the subject for years to come. Jim has been a reliable resource for me for many years in my studies and work in the field of astrolabes. Anyone that wants to look into all of the nooks and crannies of this fascinating subject will have to have his book.
Malcolm Barnfield. Sundial Maker,
The Astrolabe is an exhaustive examination of the astrolabe, quadrants and other stereographic instruments, covering their history, theory, construction (including the mathematics), practice and usage. Following its precise instruction, I have successfully constructed a universal astrolabe and a double sundial. Projects I had never attempted before and I gained valuable trigonometric knowledge and understanding in the process.
I thoroughly recommend it to the novice and expert enthusiast alike.
Dr. Edward S. Popko, Woodstock, NY
The astrolabe is one of the most significant scientific
instruments of all times. What other instrument has been in continuous use
for nearly 2000 years? It solved the critical problems of its day and continues
to be admired for its ingenuity and usefulness.
The Astrolabe focuses on the instrument itself. Morrison
retraces the astrolabe's evolution over the ages and shows how their designs
changed and their inscriptions evolved to serve its users. He even hints
at its astrological uses where one's fate might rest with the rising or
setting of a lucky star.
Morrison fast forwards the astrolabe to modern times.
He shows how, with dedication, you can make your own surprisingly accurate
and beautiful astrolabe. Everything is included: modern star positions,
formulas for making graphics and examples of recently crafted instruments.
Anyone interested in the history of science or fields
like astronomy, navigation or surveying will be astonished at the variety,
beauty and utility of the astrolabe.
Morrison's book is beautifully illustrated, and supported
by a series of useful and instructive appendices.
Col. Keith E. Brandt, M.D., ASAF Flight Surgeon at NASA's Johnson Space Flight Center.
I have read the majority of the books on western
astrolabes and there is more packed into this volume than I've seen in a
whole shelf-full of all the other astrolabe books. I don't just want to
know about the historical instrument, I want one that I can use in the medieval
way, but with accurate results. The Astrolabe is a treasure trove for making
historically accurate instruments with full modern functionality. Not only
astrolabes, but a whole host of other instruments I've never seen mentioned.
Ordering The Astrolabe
The Astrolabe is available on Amazon.com or directly from the publisher. If Amazon is out of stock or you would like a signed copy at a slightly reduced price, send a note to Janus at janus.astrolabe@verizon.net to make arrangements.
Contact the publisher, Janus at janus.astrolabe@verizon.net, for information on discounts.
A hard cover edition published by Classical Science Press is now available. See http://www.classicalsciencepress.com/index.html for information and pricing. This edition will not be available on Amazon.
We sometimes have a copy with minor flaws that we make available to teachers and students at cost. Contact Janus for details.
A few small details have been identified and fixed since the initial printing. Errata pages are available. Just send me the printing date of your copy, which is on the copyright page in small print toward the bottom of the page, and I would be happy to send any applicable corrections as a small PDF.
Here is the Table of Contents with a few of the figures from the book:
Contents
Chapter 1 - The Astrolabe
What is an Astrolabe?
An Instrument with a Past and a Future
The Principle of the Astrolabe
The Parts of the Astrolabe
The Front of the Astrolabe
The Rete and Rule
The Back of the Astrolabe
An Illustrated Example
Types of Astrolabes
The Spherical Astrolabe
The Planispheric Astrolabe
Universal Astrolabes
Astrolabe Quadrants
Horizontal Instruments
Astrolabe Clocks
Computer Astrolabes
Chapter 2 - A Concise History of the Astrolabe
Foundations of the Astrolabe
Development of the Astrolabe
Prayer Times
Astrology
Refinement of the Astrolabe
Decline of Astrolabe Popularity
Chapter 3 - The Stereographic Projection
Why the Astrolabe Works
Principles of the Stereographic Projection
Application of the Stereographic Projection to the Planispheric Astrolabe
The Half Angle Theorem
Stereographic Projection Proofs
Chapter 4 -The Planispheric Astrolabe Front
The Mater and Throne
The Limb
The Plate
Plate Interior
Twilight Arcs
Unequal Hours
Other Hour Arcs
Houses of Heaven�
Some Special Plates
The Plate of Horizons
Plate for 0� and 90�
Plate of Ecliptic Coordinates
Chapter 5 - Drawing the Astrolabe Plate
The Equator and Tropic of Cancer
Horizon and Almucantar Projection
Graphical Horizon Construction
Altitude Circle (almucantar)Pprojections
Almucantar Center Projection
Graphical Altitude Circle (almucantar)Pprojections
Almucantar Alignment with Meridian
Almucantar Separation
Azimuth Arc Projections
Graphical Azimuth Arc Construction
Unequal Hour Arcs
Islamic Prayer Times
Equal Hour Arcs
Houses of Heaven
Other Graphical Layout Methods
The Dastur
Hartmann's Method
Chapter 6 - The Rete
The Ecliptic
Dividing the Ecliptic
Star Positions
Mediation
A Modern Rete
A Celestial Navigator's Rete
Chapter 7 - The Rule
Making the Rule
Chapter 8 - The Astrolabe Back
The Back of European Astrolabes
The Altitude Scale
The Solar Longitude Scale
The Calendar
Eccentric Calendar
Drawing the Eccentric Calendar
Concentric Calendar
Making a Concentric Calendar
The Shadow Square
Drawing the Shadow Square
The Diagram of Unequal Hours
Using the Unequal Hours Diagram
Equal Hour Scale
Equal / Unequal Hour Conversion Scale
Using the Equal / Unequal Hour Scale
Drawing the Equal / Unequal Hour Scale
The Back of Islamic Astrolabes
Shadow Scales
The Sine/Cosine Scale
Using the Sine/Cosine Scale
Making the Sine/Cosine Scale
The Cotangent Scale
Using the Cotangent Scale
Drawing the Cotangent Scale
The Arcs of the Signs
Drawing the Arcs of the Signs
Drawing the Sun's Noon Altitude Curves
The Graph of the Azimuth of the qibla
Drawing the Graph of the qibla
Other Scales on the Backs of Islamic Astrolabes
Lunar Mansions
Calendars
Astrological Scales
A Modern Astrolabe Back
Using the Modern Astrolabe Back
Making the Modern Astrolabe Back
Chapter 9 - Sample Problems
Chapter 10 - The Astrolabe for Southern Latitudes
The Plate
The Rete
The Rule
Chapter 11 - Calculation Summary
Tropics
Horizon
Almucantars
Azimuths
Rete
How Accurate is an Astrolabe?
Chapter 12 - Universal Astrolabes
Chapter 13 - The Saphea Arzachelis
The Saphea Universal Astrolabe
Saphea Scales
Parallels
Polar Arcs
The Regula and Brachiolus
Uses of the saphea
The Planispheric Astrolabe
Making the Saphea
The Lamina Universal and the "Mathematical Jewell"
Peter Apian's "Meteoroscope"
The Quadratum Nauticum
Chapter 14 - Orthographic Astrolabes
The Orthographic Projection
The Organum Ptolemei
The Orthographic Astrolabe
The Origins of the Rojas Astrolabe
The Rojas Astrolabe
Using the Rojas Astrolabe
Making the Rojas Astrolabe
The Regula and Cursor
Chapter 15 - De la Hire's Astrolabe
Using the de la Hire Astrolabe
Making the de la Hire Astrolabe
Calculation Example
Chapter 16 - Quadrants
Introduction
The Horary Quadrant (quadrans vetus)
History of the Horary Quadrant
Making a Horary Quadrant
Accuracy of the Horary Quadrant
Chapter 17 - The Astrolabe Quadrant
Introduction
Introduction to the Astrolabe Quadrant
The quadrans novus
The quadrans novus arcs and scales
The quadrans novus Interior
Scales
Stars
Right Ascension
Using the quadrans novus
Position-Related Problems
Time-Related Problems
Making the quadrans novus
Chapter 18 - The Prophatius Quadrant
Using the Prophatius Quadrant
Making the Prophatius Quadrant
Chapter 19 - Gunter's Quadrant
Introduction
Description
Using Gunter's Quadrant
Making Gunter's Quadrant
Chapter 20 - Sutton's Quadrant
Introduction
Description
Using Sutton's Quadrant
Using Sutton's Quadrant
Making Sutton's Quadrant
Sutton's "Small Quadrant"
Chapter 21 - Horizontal Instruments
Introduction
Description
Hartmann's "Compast"
Time Measurement with the Horizontal Instrument
Oughtred's Double Dial
Using the Horizontal Instrument
Using the Double Dial
Making the Horizontal Instrument
The Horizontal Projection Quadrant
Chapter 22 - Astrolabe Variations
van Maelcote's Astrolabe
Using van Maelcote's astrolabe
Making van Maelcote's Astrolabe
The Linear Astrolabe of al-Tūsī
Islamic Astrolabe Variations
Planisphere
Making a Planisphere
Other Astrolabe Related Devices
Chapter 23 - Astrolabe Clocks
Monumental Astrolabe Clocks
Personal Clocks with Astrolabe Dials
The Ulysse-Nardin "Astrolabium Galileo Galilei"
Chapter 24 - Astronomical Background
The Celestial Sphere
Equatorial Coordinates
Ecliptic Coordinates
Mediation
The Sun's Position
Time
Telling time
Sidereal Time
Chapter 25 - Astronomical Calculations
Tranformation of Coordinates
Time in Astronomical Calculations
The Sun's Position
Stellar Precession
The Equation of Time
Calculating Time
Chapter 26 - Computers and Astrolabes
Introduction
Simple Astrolabe Programs
Some useful routines
PostScript
Chapter 27 - Design, Layout and Fabrication
Design
The Back
Fabrication Alternatives
Appendix - Star Positions
Appendix - Solar Data
Glossary
Bibliography
Acknowledgments
Index
Components
There was almost nothing available about astrolabes when I first became interested in them 30 years ago. At first, all I wanted was a reference that explained how and why astrolabes work and a guide to understanding the scales on old instruments. I quickly moved on to wanting to understand how to draw the astrolabe scales, but there was nothing available. I went so far as to translate Henri Michel's Traité de l'Astrolabe into English in an attempt to get what I needed. It was an interesting and rewarding challenge, especially since my French is not all that good, but the result was still short of what I felt I needed, particularly in the analytic design details, so I had to do it myself. It was frustrating but fun to work out the math to design an astrolabe and to write programs that would draw a working instrument. I was fortunate that my work required frequent trips to Europe and I was able to establish relationships with some of the scholars who have studied the evolution and history of pre-telescopic instruments and, through them, began to tap into to the historical literature.
Then, as they say, one thing led to another, and I devoted myself to learning all I could about all types of astrolabes and their history. The lack of readily available information about astrolabes led to starting this web site and offering The Personal Astrolabe and The Electric Astrolabe in an ongoing attempt to make astrolabe information more accessible.
I wanted to produce the book that I wished had been available when I was getting starting and would be interesting and useful to any educated person with an interest in astrolabes, regardless of background.
The Astrolabe is the culmination of that effort.