It is with deep regret that due to the death of James E. Morrison we are unable to continue the Personal Astrolabe part of our mission.
We are unable to accept any orders, make astrolabes or respond to correspondence. Unfortunately, any unfulfilled orders will not be completed and all correspondence will be unacknowledged.
We are sincerely sorry and we apologize for any inconvenience.
The bulk of this page is still available for your information and enlightenment.
In the meantime, please take a look at The Electric Astrolabe.
The Personal Astrolabe
The Astrolabe: the original astronomical computer
The Personal Astrolabe from Janus is an inexpensive astrolabe recreation that makes the joys and mysteries of the astrolabe available to everyone. Most astrolabe reproductions are intended to teach you a little about astrolabes but are not intended to be used. The Personal Astrolabe teaches you about astrolabes, and is also a useful instrument. The Personal Astrolabe is the most accurate astrolabe ever made. Period.
It is called The Personal Astrolabe because each instrument is custom made for you, imprinted with your name and city, and includes a set of problems worked specifically for your instrument. The Personal Astrolabe comes with a 50 page wire bound book that explains astrolabe use, theory, history and includes the necessary astronomical background.
The Personal Astrolabe is 7 inches by 8.3 inches (slightly larger than most classic instruments). The Personal Astrolabe is not a kit. It is a fully functional astrolabe, assembled and ready to use. It is produced by printing the components on a high resolution printer on heavy card stock. The front and back are accurately aligned using special tooling, drilled, cut out, laminated in plastic, recut and assembled. The rete of The Personal Astrolabe is printed on transparent material and includes 150 stars arranged in familiar constellations.
All astronomical values are calculated for each instrument including the obliquity of the ecliptic, the time of the vernal equinox for your longitude, aphelion and perihelion, and stars are rigorously precessed to the date of the instrument.
Each Personal Astrolabe is calculated for your latitude and longitude to the nearest minute of arc, and for any date you choose (we have made instruments for as far back as 2800 BC). We recommend 2010 or 2014 as the year for current instruments. These years are halfway between leap years and somewhat of an average for the date and time of the vernal equinox on the back calendar scale. Additional plates for each 5° from 25°, a plate for all horizons, a plate for 0° and 90° latitude and a plate of celestial latitudes are included. Your Personal Astrolabe can be used anywhere within several hundred miles of your home with good accuracy. The Personal Astrolabe is surprisingly rugged. Instruments made 15 years ago are still in use, with little sign of age.
The purpose of The Personal Astrolabe is to draw people into the history of astronomy by offering a fully functional astrolabe at an affordable price. We feel strongly that cost should never be a barrier to education. We have shipped over 6,200 astrolabes to 60 countries since its introduction. We are proud that many, if not most, of the astrolabes we have made are the first ones ever made for their location. It is possible that more people have become familiar with astrolabes through The Personal Astrolabe and The Electric Astrolabe than all previous publications combined.
The Personal Astrolabe is also available for southern latitudes.
Two models are offered:
- The Classic Edition of The Personal Astrolabe recreates a 16th century European astrolabe, and will be valued by anyone with an interest in the history of astronomy and timekeeping.
- The Modern Edition of The Personal Astrolabe applies astrolabe principles to an instrument that uses modern terminology and time keeping. The rete of the Modern Edition of The Personal Astrolabe is divided directly by the calendar and can be set in a single step. The kidney shaped scale on the back is the equation of time which is used to convert from apparent solar time to the time in your time zone. The Modern Edition of The Personal Astrolabe is attractive to amateur astronomers, astronomy students and anyone with an interest in astronomy. It is also in use at innovative colleges and universities, secondary and elementary schools around the world for teaching the principles of positional astronomy.
Janus (pronounced JAY-nus) is named for the Roman god of doorways and beginnings. Janus is usually depicted as having two faces: one looking forward and one looking back to remind you that the future is a product of the past. The spirit of Janus the god perfectly describes the objectives of Janus the company. Janus exists for one and only one reason; to make astronomy education more interesting and more fun. This objective is accomplished by making high quality, inexpensive recreations of historical astronomical instruments available for astronomy education.