All the applications are written using the Java language. This has the advantage that they can be run on any platform but means they need to have a Java Runtime Environment installed. This can be freely downloaded from the Oracle site that has versions for different platforms. Accept the licence agreement and download the relevant JRE.
Mac OSX: Download the file jre_8uxxx.maxosx-x64.dmg. Double-click the dmg file and install the JRE
64 bit operative system: Download jre_8uxxx-windows-x64-exe and run the exe file
32 bit operative system: Download jre_8uxxx-windows-i586-exe and run the exe file

The Macintosh Gatekeeper system may object running the applications and even urge you to move the application to the trash. The way to get around it is to double-click the application with the CTRL key pressed. In the dialog that appears click the menu item Open. In the dialog that appears: “xxx is an app downloaded from the internet. Are you sure you want to open it?”, you choose “Open”. This will only occur the first time.

JPlanet is a Java application that computes the location of the sun, the moon and the planets visible to the naked eye for any time and any place on earth. It also contains a rudimentary star catalog (400 stars). For more information see the manual that goes with the download. There are two version MacJPlanet for Macintosh OS X (10.4+) and PCJPlanet for PC.



SEATools contains the several applications implementing many of of the calendars in Southeast Asia and India:

SEAC implements the Thai and Burmese calendars, 

SEACX does the same but includes som advanced features. The applications give the location of the planets computed according to the traditional methods in SEAsia, based on Faraut: Astronomie Cambodgienne, Hanoi, 1910. Besides there are many other options in the application like the possibility of seaching for cyclic days and lagna computations. In SEACX it is possible to compute shadow lengths and search for special duang configurations. 

HIC inplements three Indian calendars the Old Suryasiddhanta, the modern Suryasiddhanta, and the Aryabathiya. There are detailed manuals for these programs. Included in the SEATools is also an implementation of the Balinese PAWUKON calendar and the lunar calendar (PAKKHAKHANANA) of the Thai King Rama IV (Mongkut). There are versions for both MacOS and Windows for all the applications.


DivHalo contains Java applications for investigating halos in divergent light. The package includes two versions, one for Windows PC, the other for Mac OSX. You may have to download the Java JRE from Oracle . The main application simulates divergent light halos. The result of a simulation can be exported and then imported in the Halo viewer application that displays the spatial locations of the crystals.  


LundClock contains Java applications that emulate the 14th century astronomical clock in the Cathedral in Lund, Sweden. The package includes two versions, one for Windows PC, the other for Mac OSX each with two applications, one with a rather large clock, the other one of a more modest size.


BabChron is a Java application that converts from the Babylonian Calendar from 626 B.C to A.D.75 based primarily on the standard work of Parker and Dubberstein, corrected with new data from Hunger and Sachs: Astronomical Diaries. The zipped archive contains a .jar file for Windows users and an application package for Mac OX users as well as a small manual. The data file BabChron.txt must reside in the same folder as the main application.


Szyzigy is a Java application for finding the time of the phases of the moon for times 2000 BC to AD 4000. Phenomena is a similar Java application for finding the "phenomena" of the planets. These are for the inner planets: inferior conjunction, superior conjunction, first and second stations (standstills), maximum east and west elongations. For the outer planets the phenomena are: conjunction, opposition, first and second stations. The applications can be run Macintosh or Windows having at least Java 1.5 implemented. The applications are both including short manuals packed in the zipped file "Phenom" below.


Galilean Moons is a Java application for investigating the four Galilean moons of Jupiter. The application uses Meeus's very accurate algorithm to compute the locations of the moons. The application gives times for occultations and eclipses of the moons. A short manual is included. The package includes two versions, one for Windows PC, the other for Mac OSX. 

Galilean Moons

Pathithin is a Macintosh Java application that draws a Thai "Patithin", a diagram and table of the locations of the planets for a given month/date according to South-East Asian ideas of the universe. The algorithms faithfully reproduce the schemes presented in the classical Luang Wisandarunkorn: Khamphi Horasatr Thai, Bangkok, 1965. 


Eclipse Predictor is an instrument for predicting solar and lunar eclipses take from Philippe de la Hire, Tabulae Astronomicae, AD 1702. It contains materials and instruction to construct a replica of an eclipse predicting volvelle.

Eclipse Predictor

Astromodels (zipped) contains eleven Excel applications that simulate the algorithms of several famous astronomers.


1. Almagest.XLS implements Ptolemy's astronomical models.

2. HandyTables. XLS implements Ptolemy's later updated version.

3. The Tables of Muhammad Ibn Mûsâ Al-Khwârizmî.

4. Al-Battânî.XLS implements the Tables of Al-Battânî.

5. The Toledan Tables. These tables are rather similar to the tables of al-Battânî but uses so called trepidational precession.

6. AlfonsoTab.XLS computes the locations of the planets based on the Alfonsine Tables, constructed under king Alfonso X in 11th century Spain. These tables are essentially a somewhat improved version of Ptolemy's tables in the Almagest.

7. The Prutenic Tables feature Copernicus' model of the planetary system as published by Erasmus Reinhold in A.D. 1551.

8. Streete.XLS , for the sun, moon and planets, is based on Thomas Streete: Astronomia Carolina from 1661.

9. Tycho.XLS uses Tycho Brahe's model for the orbits of the Moon and the Sun as presented in his "Astronomiae Instauratae Progymnasmata".

10. The tables of Vincent Wing (AD 1619-1668).

11. The Rudolphine Tables.


Streete (zipped) contains the three PDF documents: 

a) The full text of the 1661 edition of Astronomia Carolina, 

b) The tables that go with the text,

c) A small commentary with some biographical notes on Thomas Streete, the mathematical background of the tables, and a list of errata in Streete's text.


An Excel workbook, still incomplete, but featuring Cassini's models for the Galilean satellite Io.