Spectrometer 6" circle, 30 seconds of an arc, vernier readable by two opposite verniers.
| RSP-601 | | Spectrometer 6" circle, 1 minute of an arc, vernier readable by two opposite verniers. |
| RSP-630 | | Spectrometer 6" circle, 30 seconds of an arc, vernier readable by two opposite verniers. |
| RSP-701 | | Spectrometer 7" circle, 1 minute of an arc, vernier readable by two opposite verniers. |
| RSP-730 | | Spectrometer 7" circle, 30 seconds of an arc, vernier readable by two opposite verniers. |
| RSP-720 | | Spectrometer 7" circle, 10 seconds of an arc, vernier readable by two opposite |

