Photographic Observations

The naked eye is able to detect meteors down to approximately +7mag under excellent circumstances in the vicinity of the center of the field of view. Advanced video techniques permit detection of meteors to +8mag, and radar meteors as well as telescopic ones may be as faint as +11mag. Photographic methods can hardly compete with these. But the effort to be spent for the equipment of observation and reduction is much lower than e.g. for video systems. For this reason photographic observations belong to the standard repertoire of the amateur astronomer.

Photographs do not only look nice, they also contain valuable information that can be used for further analysis. Although the sensitivity of the films sets the limit to rather bright meteors, the great advantage of meteor photography is its accuracy in positions. This allows to determine of individual meteoroids or of meteor showers very accurately:

  • the height in the atmosphere. Heights vary from 15 to 140 km.
  • the radiant, that is the direction (constellation) from which meteoroids enter the atmosphere.
  • the velocity. Velocities vary in the range from 11 to 72 km/s.
  • the deceleration. Decelerations vary from hardly measurable (shower meteors) to 50% of the initial verlocity (very slow meteors of asteroidal origin).
  • the mass. Masses vary from 0.01 g to thousands of kilograms.

The deceleration gives information regarding the composition of the meteoroids. From statistical samples of meteor heights several distinct groups with different genetic origins have been deduced.

The radiant and velocity of a meteoroid yield its heliocentric orbit. This allows to associate meteoroid streams with parent comets. Famous examples are 109P/Swift-Tuttle for the Perseid stream and 55P/Temple-Tuttle for the Leonid stream.

You can also find more information on the IMO’s Photographic Commission.