Fireball


Fireball it's a free software to calculate atmospheric trajectory and heliocentric orbit of meteoroids. The observed trajectory is presumed rectilinear and the Earth spherical. For finding the trajectory of a fireball in the terrestrial atmosphere, it is possible to make use of the observations of its apparent path from two or more points. In the majority of cases it is difficult to establish which points of the apparent paths are simultaneous. Therefore, the method of determination of the true trajectory must be so devised that it would not be necessary to rely on the simultaneous points of the apparent trajectories. In Fireball, the observed points are not simultaneous.

System requirements:

  1. Microsoft Windows 98,ME,2K,XP (tested with 2K and XP)
  2. RAM (the more the better ...)
  3. about 300 KB free disk space for installation

Installation Procedure:

Extract all files from Fireball.zip into a folder of your hard disk. Double click on the program to start. The program don't require to update system files in order to run.

Unistallation procedure:

Simply delete the Fireball folder.

Getting help:

In order to calculate atmospheric trajectory and orbit of meteoroids, Fireball needs:

  1. Data and hour (Universal Time) of the observed fireball
  2. Geographical location of two observer that observed the same fireball
  3. Equatorial coordinates of two trajectory points from observer number 1
  4. Equatorial coordinates of two trajectory points (not the same of observer 1) from observer number 2
  5. Duration of the fireball from the two observers

Fig. 1. Observers geometry for fireball atmospheric trajectory.

Press the button to calculate atmospheric trajectory. The file "Trajectory.txt", with all the data, will be written in the Fireball folder. The most important data are written also at the bottom of the window dialog.

Check the resulting mean velocity value. If you want an orbit for this velocity value press the button otherwise put a new value and press. The file "Orbit.txt" with all the data will be written in the Fireball folder.

Correction applied to atmospheric velocity to obtain eliocentric value:

  1. Earth's rotation
  2. Diurnal aberration
  3. Terrestrial gravitation
  4. Earth's orbital motion

No correction for atmospheric deceleration.

Fig. 2. Fireball windows.

Example:

As example there are two output file: "Trajectory_example.txt" and "Orbit_example.txt". These file was obtained with the following data: 


Fireball IT20020812

Year: 2002   Month: 8   Day: 12   UT: 20.58333333

Observer 1

Lat: 46.283°   Long. 11.50°  Quote: 990 m
Start AR: 284.14°  Start Dec: 39.76°
End AR: 253.63°    End Dec: 46.98°  Duration: 2 s

Observer 2

Lat: 45.640°   Long. 10.83°  Quote: 1000 m
Start AR: 357.24°  Start Dec: 58.66°
End AR: 13.23°    End Dec: 77.96°  Duration: 2 s

Press "Trajectory"

Put "Mean velocity=30.0"

Press "Orbit"
More examples

Problem of Standard Deviation:

The values computed depend on the accuracy of observational values, on the accuracy of equatorial coordinates and time data. The standard deviation for the output values can be computed numerically by repeating the computations with a small change of the input parameters.

Legal notice:

Fireball is Copyright (c) Albino Carbognani. You may freely download and use the software for non-commercial purposes. Contact the author for permission prior to using the software for other purposes.

Disclaimer:

The author regularly uses the software on several of his computers and firmly believes that the software is without any damaging effect. Nevertheless, the author accepts no responsibility for damages resulting from use of the software and makes no warranty or representation, either express or implied, including but not limited to, any implied warranty of merchantability or fitness for a particular purpose. The software is provided "AS IS" and the author does not assume or accept any risk by its use.

Bibliography:

  1. C. Buil, "Meteors" (in P. Martinez, "The Observer's Guide to Astronomy", Cambridge, 1994).
  2. A.D. Dubyago, "The Determination of Orbits", MacMillana Company, 1961.
  3. T.E. Sterne, "An Introduction to Celestial Mechanics", Interscience, 1960.
  4. A.C.B. Lovell, "Meteor Astronomy", Clarendon Press, 1954.

DOWNLOAD FIREBALL

Albino Carbognani - Italy
Web: http://www.fis.unipr.it/~albino
Email: albino@fis.unipr.it

ITASN, ITAlian Superbolide Network.