Orrery Application for Ewe
Version 1.0*


Dictionary Definition:
Orrery (or-rery), n. [Charles Boyle - 1731 4th Earl of Orrery] an apparatus showing the relative positions and motions of bodies in the solar system by balls moved by wheelwork.

The first orrery was conceived by English clockmaker and inventor George Graham (c.1674-1751) around 300 years ago. This initial model only showed the earth-moon system which orbits our Sun. Graham gave the design of this original model to the celebrated London instrument maker John Rowley, who was commissioned to make one for his patron Charles Boyle (1674-1731). Boyle's patronage of Rowley soon led to the elaboration of Graham's invention so that it included all the known planets and some moons of the solar system.

Orrery.ewe is an application for Ewe enabled computers to show the Solar System in action.
It graphically shows and animates the positions of the eight planets with respect to the Sun, as well as displaying angle and distance information.

To use this version of Orrery you must install a Ewe¹ VM (Virtual Machine) on your computer. Ewe is a version of Java which runs on a variety of desktop and handheld computers. It is very compact and efficient. It uses only about 2 Mbytes of memory.
To learn more about Ewe please read the introduction on the Bray Mobile Applications page.

Orrery is an application that shows a simulated view of the Sun and its eight planets from above the orbit plane. It will also display:

The Orrery display can be animated with time steps as specified.

The dwarf planet Pluto is included in a very limited way. You can choose to have Pluto shown at a fixed position in the "Equal Distance" view, but no data is given for it.
It takes Pluto 90465 days to circle the Sun! In the animation mode of Orrery, Pluto would show very little motion. No "planetary theory" has been constructed for Pluto because since it discovery in 1930 it has moved less than 1/3 of it orbit around the Sun. Any orbital data included in this application would only be accurate for a "short period" of time.

About This Documentation

For a Quick Start read Installation. Then after trying it out please return to this documentation to learn all of the features.


Since you are reading this documentation, you have found that you have the orrery10Doc.zip archive in orrery10.zip, and the file orrery.ewe. The orrery10Doc.zip contains this documentation you are now reading. To install Orrery simply copy the file orrery.ewe as instructed below.

The first thing to do is to install the Ewe VM on your computer(s), if not already installed. Follow the instruction found on the Ewe Download and Installation Page for your computer. The Ewe installer will create directories on your computer and put the Ewe VM files in them. After Ewe is installed find the Ewe directory. For example, in a Windows Desktop it will be where you told the installer to install it, and in the Pocket PC it will (probably) be in /Windows/StartMenu/Programs/Ewe.

There is no installer for orrery.ewe, it can be put in any directory of your choice. However it is recommended that you put it in the directory with the Ewe VM. Specifically the directory in which you find 'ewe.ewe'. This will make it easier to find it if you want to change/delete it, and when you add additional applications from Bray Mobile Applications common files can be shared.

Orrery.ewe does not use your computer's registery so to unstall orrery.ewe simply delete it.

Note: No matter what Regional settings are used on your computer(s), Orrery always uses the '.' (period) as the decimal point, the ':' (colon) as the hour/minute/second separator, and the ',' (comma) as the data separator.

Orrery should be ready to run now. Find Orrery.ewe with your File Explorer, click on it to try it out!

Using the Program

Upon your first view of the Orrery display you will note that the Sun is in the center surrounded by the plants. It shows all of the planets at their correct position for the date shown in the upper right, and with their orbits equally spaced. The display is configured this way because the menu selections are 'All' and 'Equal Distance', as indicated by the two 'bullets', as seen below.

Planet Icons

Menus Items

When you tap Display at the top button row left, the menu shown on the right will pop-up. When you tap Data at the top button row center, the menu shown on the right will pop-up. This menu controls what is displayed on the Data page. (Data at the bottom button row left).

Contact Information

Orrery was created by David W. Bray, Potsdam, NY;
Copyright © David W. Bray 2005, All Rights Reserved.

The Bray Mobile Applications Page can be found at: http://davidbray.org/mobile
The Bray Palm OS Page can be found at: http://davidbray.org/palm


Orrery is freeware -- no registration is required. We hope you enjoy using it.
I would appreciate receiving e-mail about what computer(s) you are using Orrery on, and any other feedback and suggestions you would like to share with me.

This archive may be freely redistributed, provided it is made available only in its complete, unmodified form with no additional files and for noncommercial purposes only. Any other use must have prior written authorization from David W. Bray -- E-mail address on this page..

Unauthorized commercial use includes, but is not limited to:


This program is provided without warranty and the user accepts full responsibility for any damages, consequential or otherwise, resulting from its use.

Foot Notes

¹ Ewe is developed by Michael L Brereton. We are indebted to him for his outstanding software product and making it freely available. Thank you Michael!

*Changes in Version 1.0

Orrery Version 1.0 Bld:603 differs from Version 1.0 Bld:537 in
  1. Original release -- Version 1.0 Bld:537
  2. Changed to use EweVM fonts. (V1.0 Bld:603)
  3. Fixed bug in planetOE() meanAnomaly. (V1.0 Bld:603)
Bld:603 is the current release.

To be sure that your version is up-to-date check the Bld: number in the current description of Orrery at: http://davidbray.org/mobile/

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