| Answer | Crossword Clue |
|---|---|
| TELESCOPE | Optical instrument. |
| LASER | Optical instrument |
| FIELDGLASS | Optical instrument. |
| SPECTROSCOPE | Optical instrument. |
| LENS | Optical instrument |
| LENS | Optical-instrument part |
| CROSSHAIRS | Optical instrument parts. |
| EYEPIECE | Optical-instrument part |
| PERISCOPE | Optical instrument at sea. |
| PERISCOPE | Optical instrument with mirrors. |
| LENSED | Describing an optical instrument. |
| PERISCOPE | Optical instrument used in trenches. |
| OCULAR | Part of an optical instrument. |
| RETICLE | Grid in the eyepiece of an optical instrument |
| TETHYSSCOPE | Optical instrument pointed at a moon of Saturn? |
