Make your own free website on Tripod.com
The METSIM software
 
The Leonid return in 1998 and 1999 will probably be a very challenge to visual meteor observers. In fact it will be quite difficult to obtain reliable activity data from visual counts. Yet it is still unclear how to judge about the 1966 visual counts. A calibration of those data by imitating the 1966 method may provide us with more reliable ZHRs of the last Leonid return. Their method then was simply "estimate the number of meteors visible when looking at the sky for one second". This method can be simulated by the Meteor storm simulation software written by Sirko Molau, based on an idea of Hartwig Lüthen.
 
 
 
Meteor Storm Simulation 'metsim.exe'
========================= 
This program displays a meteor storm to investigate visual observing
techniques under very high meteor activity. It tries to simulate the
situation as accurate as possible. Meteors are displayed as elongated
moving objects. They do have different brightnesses, light curves,
velocities, directions, persistent trains, etc as in reality. The sequence of
shooting stars is computed with an exponential distribution. Thus, the
often reported 'cluster effects' become clearly visible. A number of
background stars make the display more realistic. 
Download the Software HERE
METSIM.EXE
To run the program, a fast PC / graphics card is necessary. The simulation
should be executed under DOS.  
It is advised to do the first simulations with a clock displayed. If the
calibration works well, the clock should run approximately in real time.

Three simulation modes are available:
* In training mode, you enter a number of meteors per second and the
  program shows you, how that will look like.
* In static test mode, the program displays a fixed number of meteors, that
  you have to estimate.
* In dynamic test mode, the simulation runs for a longer time with
  gradually changing activity. You are to estimate the meteor number each
  minute, which allows the study of systematic errors. 
On startup you can choose a number of parameters like
* the position of the field of view with respect to the radiant,
* the geocentric velocity and population index values of the meteor
  shower and
* the number of stars displayed.
The flag -help lists all available options. 
The software has some limitations:
* Effects like variable meteor numbers due to the position of the field of
  view (near zenith or horizon, near or far from the radiant) are not
  simulated, as these effects have only to be modeled properly when
  computing the ZHR. Main aim of the program is to study, whether visual
  observers are able to give good estimates of a larger number of shooting
  stars visible in a certain field of view. So, the long-time average of
  displayed meteors matches exactly the given number.
* For the same reason, there are no very faint meteors displayed, which
  are extremely difficult to see. Every observers should be able to see all
  simulated meteors, avoiding side effects from different 'limiting
  magnitudes'.
* The angular velocity of meteors and the lengths of their trails is not
  computed according to some formulae, but was intuitively adjusted to look
  realistic. This may be improved in a future release of the program. 
Please, send your questions, data files, suggestions for improvements, and
other comments to the author (molau@informatik.rwth-aachen.de).
Enjoy the simulation!
Sirko Molau 

Back to CIAA Main Page