 |
| |||
| prism | |||
| cross-staff head | |||
| right angle prism | |||
| totally reflecting prism; optical square (surveying: internally reflecting prism used to turn a beam of light through precisely 90° or 180°) | |||
|
| |||
| prism | |||
| cross-staff head | |||
| right angle prism | |||
| totally reflecting prism; optical square (surveying: internally reflecting prism used to turn a beam of light through precisely 90° or 180°) | |||