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1988-06-30
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+--------------------------------------------------------------------+
| STAR CLUSTER SIMULATOR |
+--------------------------------------------------------------------+
Introduction
------------
This program graphically simulates the motion of objects in space
(stars, planets, spacecraft, etc.).
To run the program, perform the following steps:
1) type "cluster"
2) read a data file ('R' option).
3) execute simulation ('X' option).
Explanation
-----------
Cluster is a program that simulates stellar mechanics, i.e. the
effect of gravity on the motion of objects in space. It can be used
to model the motion of stars in a cluster, or of planets around a sun.
To set up a simulation, you need to specify the location, velocity
and mass of the bodies. This is done by creating a data file which
lists this data for each object. (Note: The data files for cluster
use the extension ".cdt".)
The format of this data file starts with one comment line
describing the simulation, followed by a data line for each object.
Rectangular co-ordinates are used for the position and velocity. Each
line contains in sequence the x-position, y-position, z-position,
x-velocity, y-velocity, z-velocity and mass.
The position and velocity are represented in Astronomical Units
(AU). An AU is the average distance of the earth from the sun. The
basic time unit is one earth year. The masses are measured in solar
units where the mass of our sun is 1. In selecting the coordinates,
remember that the display will always be centered around the point
(0,0,0). The actual scale is determined automatically based on the
values chosen for the coordinates. For star travellers, one light
year is approximately 63.4 AU. (Hint: It's very easy to use a
spreadsheet to create these data files.)
The simulation can be run at a number of speeds for greater or
lesser accuracy. The program also automatically reduces the selected
time increment when the objects get very close to maintain a reason-
able overall accuracy.
Several sample data sets are included with the distribution
package.
References
----------
This program was inspired by the article "A Cosmic Display" by
A.K. Dewdney which first appeared in Scientific American and was later
republished in the book "The Armchair Universe" (which I highly
recommend).
Technical Information
---------------------
Cluster is written in Turbo C, Version 1.5, using the Borland
Graphics Interface (BGI) library. The program includes graphic
drivers for the following display devices: CGA, EGA, VGA and Hercules
monochrome. For calculations, it uses the math emulation library and
will run on machines with or without a math coprocessor. The actual
source code is approximately 16K in size and is available to
registered users.
Registration
------------
Your financial support will encourage the programmer and entitle
you to a future version of this program.
[1] For $10 you become a registered user which entitles you to a free
upgrade to the next version, and notification of subsquent revisions.
[2] For $20 you become a registered hacker and will be sent the source
code of the current version, and notifications of future revisions.
Yes, I wish to be a real celestial mechanic:
Name: __________________________________________________________
Address: __________________________________________________________
__________________________________________________________
City: _______________________________ State: ____ ZIP: _______
User ($10) ___ Hacker ($20) ____ Total Enclosed _______
What version of the program do you have ? ________________________
Where did you get a copy of this program ? _______________________
Do you have any suggestions for additions to the next version ?
Make checks payable to: David E. White
Mail to: David E. White
55 Bow Street
Arlington, MA 02174