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Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
[email protected]
Discover the Amazing Astrolabe!
Join the thousands of astronomy enthusiasts around the world that have rediscovered the
astrolabe. The astrolabe was the most popular astronomical instrument from before 1000
to about 1650 AD and is enjoying renewed interest. Scholars have probed its rich history
and museums have acquired instruments and placed them on display for the public to
appreciate. New publications explaining how astrolabes were used and made are
available. The ordinary person is left wanting more: to actually work an astrolabe. But
old instruments sell for many thousands of dollars and cardboard reproductions, while
communicating basic astrolabe principles, are not useful for solving astronomical
problems. Affordable metal astrolabes are more decorative than useful.
The Personal Astrolabe from Janus answers the need for a useable and affordable
working astrolabe. The Personal Astrolabe is the most accurate astrolabe ever made,
period. Each instrument is custom made for you, accurately calculated for your location
for any time period you chose and laminated in plastic for long life. The application of
computer technology to astrolabe design and manufacture brings the special capabilities
of the astrolabe to the modern world at a price anyone can afford.
Each Personal Astrolabe is completely assembled and includes a clearly written bound
book on astrolabe principles, uses, theory, history and astronomical background. Fully
worked sample problems for your custom instrument are included.
What is an Astrolabe?
An astrolabe is a portable astronomical computer for solving problems that involve time
and the position of the Sun and stars. For example, an astrolabe can be used to find the
time of sunrise and sunset for any day of the year, locate any celestial object, find the
time during the day or night and to solve literally hundreds of other problems. The design
of the astrolabe is very intuitive which makes it ideal for learning fundamental principles
of astronomy. In addition, the astrolabe opens the door for a fascinating look at the
history of astronomy and time keeping. The Personal Astrolabe can be used as an
astronomy learning aid, a fully functional instrument and as a window to history.
Here are some comments from satisfied users of the Personal Astrolabe:
“The deal of the century.”, C.R., Oregon
“I am impressed with the quality and accuracy.” R.P, California
“The Personal Astrolabe book is excellent, lucid and interesting.”, A.W., Pennsylvania
“An outstanding achievement.” Dr. G. S., Scotland
“I am delighted with my astrolabes.”, H.L., Massachusetts
“Fabulous. Simply fabulous”, W.S., Germany
“An admirable product of superior quality.”, Dr. A.B., Florida
The Personal Astrolabe costs less than a dinner out and opens a lifetime of education and
enjoyment.
Order your Personal Astrolabe today and join the fun!
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
THE PERSONAL ASTROLABE© – CLASSIC EDITION
Personal Astrolabe
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The CLASSIC EDITION of The Personal Astrolabe is a modern recreation of a classical astrolabe
in the form used in Europe from the late 14th century to the end of the 17th century, updated with
modern materials while retaining the look and feel of an old instrument, and is far more accurate.
The transparent rete includes 124 stars, most displayed in the form of constellation asterisms with
bright stars named. Star positions are accurate for the date of the instrument. The CLASSIC
EDITION includes unequal hour arcs and, as an option, can include the astrological “Houses of
Heaven” commonly found on Renaissance instruments. An instrument can be made for any year
or location. For example, if you are studying Chaucer’s astrolabe treatise, a Personal Astrolabe
can be made for 1390 Oxford and inscribed with Chaucer’s name if you wish. Annotation can be
printed in Latin or your native language (see ordering instructions for supported languages).
The back of the CLASSIC EDITION contains the traditional scales for converting the date to the
position of the sun, finding the unequal hour from the sun’s altitude and has the traditional
“shadow square”. The calendar scale is customized for your longitude. Also shown is the
longitude of perihelion and aphelion for the year of the instrument.
The instrument is printed on heavy card stock, accurately drilled and laminated in plastic for
permanence. A 50+ page wire bound booklet on astrolabe use, theory and history and containing
necessary astronomical background is included along with fully worked examples for your
instrument.
The Janus PERSONAL ASTROLABE–CLASSIC EDITION is ideal for learning about astrolabes, as
an astronomy education aid or as a fully functional instrument.
Classic Edition - Only $29.00 - US postage and handling included
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
THE PERSONAL ASTROLABE© –MODERN EDITION
Personal Astrolabe
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Two models of THE PERSONAL ASTROLABE are offered. The Modern Edition of the Janus
PERSONAL ASTROLABE is an astrolabe updated for modern use. The ecliptic is divided directly by
the calendar, which allows you to set the date and time in a single step and additional annotation
has been added for ease of use. The scales on the back include solar longitude and conversion
from apparent solar time to local zone time.
The Modern Edition of THE PERSONAL ASTROLABE is particularly well suited for basic
astronomy education since it retains all of the features that make astrolabes such wonderful
learning tools while discarding astrolabe elements that are no longer in wide use.
Like all Janus astrolabes, the Modern Edition is completely customized for your location and is
printed on heavy card stock, accurately assembled and laminated in plastic. The finished
instrument is 7 in. by 8.3 in. and is fully assembled. A 50+ page wire bound booklet on astrolabes
use and theory is included along with fully worked examples for your location.
The Modern Edition of THE PERSONAL ASTROLABE is invaluable as a teaching aid and useful as
a working instrument. It will treasured by anyone of any age with an interest in astronomy
MODERN EDITION — only $29.00 - US postage and handling included
A Combination Package containing both editions and a single book describing
both models can also be ordered:
Combination Package – only $40 – US postage and handling included
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
THE ELECTRIC ASTROLABE
The Electric Astrolabe is a computer planetarium program in the form of an astrolabe.
This ageless format provides a unique view of the sky that is useful to the beginner as
well as the experienced astronomer. The Electric Astrolabe is fully animated, allowing
you to enjoy the majesty of the heavens as the stars and planets whirl through the sky. In
addition to the astrolabe display, the Electric Astrolabe includes an animated orrery of
the planets as they orbit the Sun and accurate information on the positions of the Sun and
planets and pictures of the phase of the Moon, the position of Jupiter’s moons or Saturn’s
rings. You can view the sky from any location on Earth or at any time in the past or
future. Observe the position of the Moon that lighted Columbus’ landing in the New
World or recreate historical astronomical events such as the great planetary conjunction
of 1953 BC.
The figure below is of the main display screen and is taken directly from the display. It
shows the sky at the instant Neil Armstrong first set foot on the Moon.
In addition to the normal astrolabe functions, the astrolabe display includes 150 stars, all
109 Messier objects and the planets out to Neptune, all fully animated.
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
Other screens include an animated orrery of the planets orbiting the Sun, full numerical
planetary positions, Help, and the ability to customize the Electric Astrolabe to your
location and taste in colors. You can also display the phase of the Moon, Jupiter’s moons,
Saturn’s rings and the phases of the planets at any time. The color of the sky above the
horizon changes from blue, through twilight gray to black depending on the position of
the Sun.
The Electric Astrolabe is easy to use. You can start exploring the heavens in minutes. A
108 page user’s guide is included.
For beginners, The Electric Astrolabe can be used as an educational tool to learn about
astronomical measurements and the astrolabe display provides the most effective way to
understand basic astronomy principles. The animation ability of the Electric Astrolabe
provides vivid demonstrations of the motion of the Sun, retrograde motion of the planets,
stellar precession and the astronomical reasons for the changing seasons. For advanced
users, the Electric Astrolabe can calculate planetary and lunar positions with accuracy
close to The Astronomical Almanac including provision for dynamical time. The Electric
Astrolabe can be used to plan astronomical observations, determine the exact time of
astronomical events for any date and location, plan events to coincide with the phases of
the Moon or simply stay in touch with what is happening in the sky. The Electric
Astrolabe also makes an extremely elegant astronomical clock.
The Electric Astrolabe is a DOS program for PC’s and is fully functional on all versions
of Windows up to XP. Under Windows Vista and 7 it can be run using DOSBox. It is not
available for the Mac.
The Electric Astrolabe is on public display at the Frankfurt (Germany) City Museum
astrolabe exhibit and has been used in a number of museum exhibits. It was described in
the March, 1994 edition of Interdisciplinary Science Reviews and was included in the
proceedings of the 50th anniversary of the Institute for the History of Science, Johann
Wolfgang Goethe University, Frankfurt, Germany.
The Electric Astrolabe can be downloaded free from the Janus web site,
astrolabes.org/electric.htm.
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
Janus Personal Astrolabes
Frequently Asked Questions
What is an astrolabe?
The astrolabe is a portable astronomical computer for solving hundreds of problems related to the time and
the position of the Sun and stars. It was the most popular and widely used astronomical instrument for
hundreds of years until it was replaced by more specialized instruments. The astrolabe was also the basic
tool for astronomy education in the Middle Ages and Renaissance. It is very easy to use an astrolabe to find
the time of sunrise and sunset, the altitude of the sun and to tell time from the stars. The astrolabe can also
be used as a star finder and as a handy reference for star positions. The book that accompanies the Personal
Astrolabe includes a set of problems that are worked specifically for your customized instrument that
illustrates many astrolabe uses and suggests many more.
Which model of the Personal Astrolabe should I order?
Our experience has been that the Modern Edition of the Personal Astrolabe is popular with students,
amateur astronomers, celestial navigators and those who wish to expand their general knowledge of
astronomy. The Classic Edition of the Personal Astrolabe is the choice of those with an interest in the
history of astronomy in general and historical astronomical instruments in particular. Of the two models,
the Modern Edition is the more useful in everyday modern life and is in regular use by hikers, sailors,
educators and astronomers around the world. Over 90% of Personal Astrolabes orders are for the
combination package. By implication, it must be a pretty good deal.
What is in the book that comes with the Personal Astrolabe?
The Personal Astrolabe book has chapters that introduce the astrolabe, explain of each of the astrolabe
components in detail including examples, solved problems customized for your personalized instrument,
how and why the astrolabe works, a concise history of the astrolabe, astronomical background, a complete
bibliography, a list of astrolabe collections and an extensive glossary. Astrolabe plates for each 5 from 25
to 60, a plate of horizons, a plate for 0 and 90 and a plate of longitudes and latitudes are included. The
additional plates can be removed from the book and inserted in the instrument. The Personal Astrolabe
book is the clearest and most complete astrolabe user’s guide in print. The book is wire bound to lay flat.
Can the Personal Astrolabe be supplied for latitudes south of the equator?
Yes. The resulting instrument is unique in the history of astrolabes as there are no other known instruments
made for southern latitudes.
Why do I need to specify a location and date for my Personal Astrolabe?
The astrolabe is based on your local horizon, which is slightly different for each latitude. Your longitude is
needed to find civil time for your zone time. The Personal Astrolabe is calculated for your exact location to
achieve maximum accuracy. It is useable over a large area and additional horizon plates are provided to
cover all of North America and Europe. A date is needed for the calculation of astronomical values that
change over time. An astrolabe made for the current time will be useable for many years. An astrolabe for,
say, 1390 would be quite different. We recommend 2018 as the design year for current instruments. 2018
is midway between leap years and is something of an average for the calendar scales.
Where can I get a brass astrolabe?
See our web site for addresses of suppliers of brass astrolabe reproductions.
See our Web pages at: http://www.astrolabes.org
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
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Order Form
18 Kingsbridge Road
Rehoboth Beach, DE 19971 USA
(302) 226-5086
[email protected]
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SHIP TO:
Name: _________________________________e-mail:_______________________________________
Address: ___________________________________________________________________________
City:_______________________________________________ State: ______ Zip: ________________
or
Postal Code:______________ City:_______________________ Country:_______________________
CUSTOMIZED ASTROLABE INFORMATION (WRITE CLEARLY AND BE PRECISE):
Name to be printed on Astrolabe (30 char max):___________________________________________
City name to be printed on Astrolabe back: _______________________________________________
Latitude: _____ _____
Longitude: ______ _____ E __ or W __.
Language: ______________________
Time Zone:________ (EST, CST, MST, PST or hours from UT)
(If you don’t know your latitude and longitude we will do our best to look it up for you)
Year of Astrolabe (any year from 4712 BC forward can be specified): ________
QTY
DESCRIPTION
UNIT PRICE INTERNATIONAL
POSTAGE
Personal Astrolabe - Modern Edition
$29.00
Personal Astrolabe - Classic Edition
$29.00
Include astrological “Houses of Heaven” on plate:
 Yes 
No
Combination Package - Both Astrolabes + 1 Book
$40.00
TOTAL DUE
Notes or special instructions: ___________________________________________________
Orders for multiple instruments should include a list of names to be printed and the latitude and longitude for
each instrument.
Make checks payable to: Janus
*
Shipping is by first class mail. See next page for international shipping charges.
Write for information on volume discounts for academic use.
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
AMOUNT
Ordering Instructions
There are several ways to order The Personal Astrolabe. You can download and print the order form from
the astrolabe web site (astrolabes.org/personal.htm) and mail it with payment to the address on the form. If
you have Adobe Acrobat, you can fill in the form and e-mail it or you can send all the ordering information
in an e-mail. Order details will be confirmed by e-mail. Payment can be via personal check, PayPal or
whatever means is most convenient for you. We are not able to accept credit cards except via PayPal.
The costs shown on the order form are for the US only. International postage rates were recently increased.
For air postage to Canada, add $6 US. For Mexico, add $8.00 US. For shipping by air post to Europe,
Australia and Africa add $12.00 US for either one or two astrolabes. Send a note for current international
postage cost to other locations. The shipping weight is 12 oz. Shipping charges are for our cost.
Please write clearly and be complete. We often have to write to clarify information that we cannot read.
This is why we ask for your e-mail address. Be particularly careful to make sure the e-mail address is
written clearly. We cannot contact you if we can't read the e-mail address and we can't even write if we
can't read the shipping address. We never use your e-mail address for any other purpose.
It is generally better to have your Personal Astrolabe shipped to your home or office instead of a post
office box if possible. We stamp the package, "Do Not Bend" eight times on both sides of the shipping
envelope, but we have had cases where considerable effort was exerted to bend the package to fit into a
post office box. Return your astrolabe package to Janus for replacement if this occurs.
The name, city and state will be printed on your astrolabe(s) exactly as they appear on the order form. The
names can be all caps or mixed case. We cannot use small caps in the names. Make the names all caps if
that is what you want, or use lower case letters (preferred) in the names. You can specify different names
and dates for the Modern and Classic Edition instruments in a Combination Package order, but both
instruments must be for the same location. The maximum length of the name to be printed on the front of
your astrolabe is 30 characters and spaces.
Be careful when specifying your latitude and longitude. We get many orders where the latitude and
longitude were copied from GPS receivers. Some GPS receivers display latitude/longitude in decimal
degrees and degrees and minutes are used on the astrolabe. We are happy to make the conversion if you
note that you are using decimal degrees. There are many tools available to find your latitude and longitude.
The most convenient are web based map sites or computer mapping tools such as Street Atlas USA or
Google Earth.
The "Houses of Heaven" are optional on the Classic Edition for several reasons. Some teachers and
students do not want such astrological material on an educational instrument. Also, for students of the
history of astronomy, several methods of defining astrological houses were used in the past that were quite
different from the convention used on astrolabes. For example, Chaucer devotes considerable space to
determining the astrological houses in his 14th century treatise, but in a different system. You would not
want the astrolabe houses on an instrument that will be used in conjunction with Chaucer's treatise.
There are only a few places on The Personal Astrolabe instrument that may benefit from translation into
your national language. We can produce your astrolabes with the month and zodiac names and other
annotation in English, French, German, Latin (Classic Edition only), Italian, Spanish, Swedish, Dutch,
Polish, Portuguese and Czeck so far. We can easily add any Latin based character set language. All we
need is for you to supply the translations (including all accents) of the month names, the signs of the
zodiac, the words for North, South, East and West and “Longitude”, “Longitude Correction” and the
abbreviation for minutes (min.) and seconds (sec.). Contact Janus if you have any questions. There is no
charge for customizing your astrolabes to a new language. The book is available only in English.
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]
Now Available
The Astrolabe
By James E. Morrison
The Astrolabe (ISBN 978-0-939320-30-1, Soft cover, 434 pp., 264 figures) is the most complete
astrolabe treatise available in English. It contains the description, use, history, theory and design
of all types of Islamic and European astrolabes, related quadrants, astrolabe variations and
astrolabe clocks. Application of computers to astrolabe design and practical advice on making an
inexpensive working astrolabe are included.
It is described in more detail at www.astrolabes.org/theastrolabe.htm.
The Astrolabe will be attractive to anyone with an interest in astronomy and its history including
amateur astronomers, celestial navigators, students and teachers.
See www.astrolabes.org/theastrolabe.htm for a more complete description and a sample chapter.
The Astrolabe is available from Amazon.com or directly from the publisher. The publisher direct
price is $40 US with US postage included. Contact Janus by e-mail at the address below for a
signed copy or to inquire about discounts.
Janus
18 Kingsbridge Road
Rehoboth Beach, DE 19971-1404
USA
(302) 226-5086
[email protected]
Janus 18 Kingsbridge Rd, Rehoboth Beach, DE 19971-1404
(302) 226-5086
[email protected]