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 distance to the Sun and Earth for each planet.
• The angular separation between the Earth and each planet.
• A matrix of distances between each of the Sun and planets. The distance units can be Astronomical Units (AU), Kilometers, and Statute Miles. (one AU is the distance between the Earth and the Sun.)
• A matrix of angular separation between each of the planets, in degrees.

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

• Installation (Must Read)
• Using the Program
• Planet Icons
• Menus Items
• Contact Information
• Foot Notes
• Version Changes

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

• All All eight of the planets are shown.

• Visible Only the planets visible with the naked eye are shown.

• Show Pluto The position of the dwarf planet Pluto will be shown in the display when it is in the Equal Distance mode, and All planets are selected. It is shown at a fixed position for the initial date shown.

• Real Distance The planet distances from the Sun are proportional to their real distances. All of the inner planets are very close together.

• Equal Distance The planet distances from the Sun more or less equally spaced.

• Log Distance The planet distances from the Sun are proportional to the logarithm of their real distances. This spaces the outer planets much closer together.

• Settings This will pop-up a dialog box to set the control values for the animation of the Orrery display.
  • Step specifies how many days the date in incremented for each animation step. This value can be negative.
  • Wait specifies how long a given animation snapshot is displayed.
  • Magnify specifies the magnification of the Orrery. Note: The position of the Orrery can be moved with the pen/mouse.
  The Animate Button, at the bottom button row right, starts and stops animation. Animation continues independent of whether a graphical or data display is active.

• About This is the usual About information. It tells you the version of Orrery and Ewe you have installed. Use this to see if your installed version of Orrery is up-to-date.

• Quit This is the obvious Quit selection. You can also Quit using the upper right hand X.

• Sun/Earth displays the distance between the planets and the Earth and the Sun. Also shown is the angular separation between the planets and the Earth and the Sun. The units of distance is controlled with last three menus discussed below.

• Planets displays a matrix of distances between the planets and the Sun.

• Separation displays a matrix of angular separation between the planets.

• AU changes the units to be Astronomical Units (AU). One AU is the distance between the Earth and the Sun.

• Km changes the units to be Kilometers

• Miles changes the units to be Statute Miles.

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

Registering

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:

• Orrery itself as a product for sale.
• Accompanying a product for sale.
• Accompanying a magazine, book or other publication for sale.
• Distribution with 'Media', 'Copying' or other incidental costs.
• Available for download with access or download fees.

Disclaimer

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

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)

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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