With two camera setups it is possible to photograph the same meteor from two different stations: double-station photography. As is generally known, such a pair of photographs allows to calculate the trajectory of the meteoroid through the atmosphere and its orbit around the sun.
When you want to experiment with double-station photography you will have to select the locations of the two stations and to determine the best point in the atmosphere to aim the cameras at. The following criteria have to be taken into account:
When choosing the locations of the stations the important parameters are the length of the baseline (distance between the stations) and the angle between the baseline and the azimuth of the active radiant. In general the following rules apply: the larger the baseline of the cameras, the larger the average Q.
The larger the angle between the baseline and the azimuth of the radiant, the larger the average Q. So, preferably the cameras should not be lined up with the radiant at any time during the night. When the radiant has an elevation higher than 45 degrees this rule becomes less important.
The first rule has a practical limit of about 200 km, in which case the two cameras have to be pointed in opposite directions towards each other. For camera batteries the practical limit is even as small as 100 km, because for larger distances the overlap in covered areas of atmosphere becomes very small. In general, any baseline larger than 50 km is allright, but smaller baselines may still be useful.
With the above introduction in mind you are ready to start using the tool called QRICHT.EXE (for MS-DOS). This tool requires the following input information:
You have to enter this information in a file that follows the format of the example file QRICHT.FRM. After that you can enter the command "C:> QRICHT filename". Then, QRICHT calculates the following figures:
So, the tool provides you with all required information to aim your cameras for double-station observations. Only it does not find the geographic coordinates of the optimal aiming point in the atmosphere. You can find this by trial and error, or you can try to apply the general rules and explanation provided in the previous sections. A good value for the height of the aiming point is 100 km. The table below shows more specific values for a few major showers. A distinction is made between photographic observations (typical Lm of +1m) and video observations (typical Lm of +6m).
|Stream||Photographic (km)||Video (km)|