The fixed target is placed on solidly installed measurement points that are equipped with a forced centering mechanism. When taking measurements with the alignment telescope, the fixed target is needed to find the reference line (alignment line).
| Target pattern | Concentric circles or Websky Gap | |
| Forced centering | Freiberg Ball | |
| Size | Target plate | 140 x 123 mm |
| Total size | 305 x 155 x 130 mm | |
| Weight | Target | 1.4 kg |
| with carrying case | 4.0 kg |
The alignment telescope is positioned on one of the fixed reference points and coarsely leveled using the circular bubble level. Then a fixed target is placed on a second reference point which is equipped with the forced centering mechanism called “Freiberg Ball”. After centering the tribrach bubble, the target is oriented toward the alignment telescope using the small viewfinder. Then the alignment telescope is coarsely oriented toward the fixed target plate, the fine adjustment is realized by means of the striding level.
The fixed target has a tribrach with a circular spirit level, the sensibility of that bubble level is 8’ per 2 mm bubble run. The viewfinder at the top of the fixed target plate is used to orient it perpendicularly to the vertical alignment plane.
The target plate itself can also be removed from the tribrach and replaced with a target that has a different pattern. Usually, concentric circles or a pattern with the so-called Websky Gap with adjustable width are used, so that the plates can be easily targeted at a distance of about 500 meters.
Example of use
- monitoring of the deformation behavior of water dams
