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Libris Britannia 4
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ASTRNOMY
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B_STAR.ZIP
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B_STAR.DOC
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1993-05-10
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47 lines
Program to calculate and animate the
position of a binary star system
The program takes as inputs the following values to calculate the view.
A) (P) The period of the binary star in real year format e.g. 1988.11
B) (T) The time of periastron passage, again in real year format
C) (e) The eccentricity of the true orbit
D) (a) The semimajor axis (in arc seconds)
E) (i) The inclination of the true orbit to the plane of the sky. 0 means that
we are seeing the orbit as it really is, a value of 90 degrees means that
we are viewing the orbit exactly edge on, a value greater than 90 means
that the direction of travel is opposite the normal anticlockwise direction.
F) (omega) The position angle of the ascending node. This refers to the compass
direction as we see it, of the ascending node of the binary star's orbit
G) (W) The longitude of periastron.
H) The year (in real form) to start the animation for.
I) The interval between successive evaluations (years, in real format).
J) The year (in real form) to end the animation for.
K) The delay in milliseconds between each update of the screen.
L) To clear the screen or to leave the image of the star on to build up a
representation of the orbit. A small 'y clears the screen else anything.
M) The name of the star. This is just for presentation purposes.
The screen can be printed out if desired by first typing in graphable to
enable dos to dumb the screen contents when <shift> <print screen> are hit.
The 7 orbital parameters that are required to specify fully a binary star's
orbit must be obtained from some other source. A good few of the better known
binary star's elements are included in the excellent book "Nortons Star Atlas".
The program will work on any computer with a EGA/ VGA graphics card installed.
If you find this program useful and continue to use it please send a donation
to the author to help with further improvements or if you have any problems
or queries about the program please contact the author :
P.J. Naughter,
Cahore,
Ballygarrett,
Gorey,
Co. Wexford,
Ireland.