
Description
The Topcon Reference Prism with Hood (monitoring) is a monitoring prism made by Topcon (part number 1042086-01).
Its absolute prism constant is -40.0 mm, which is -5.6 mm on the Leica scale.
Specifications
| Model: | Reference Prism with Hood |
| Manufacturer: | Topcon |
| MPN: | 1042086-01 |
| Status: | Current |
| Absolute constant: | -40.00 mm |
| Leica constant: | -5.60 mm |
| Constant source: | Manufacturer documentation |
| Dimensions (W × H × D): | 160×115×110 mm |
| Weight: | 740 g |
| Maximum range: | 3,500 m (Up to 1800-3500 m; minimum 1.5 m (no haze, visibility >20 km, slightly overcast) |
| Mount: | 5/8" Thread |
| Coating: | Silver coated prism in sealed canister |
| Last verified: | 21/10/2026 |
Sources
Topcon Reference Prism with Hood (monitoring) FAQ
Below is a list of frequently asked questions about Topcon Reference Prism with Hood (monitoring).
What is the prism constant for the Topcon Reference Prism with Hood (monitoring)?
The absolute prism constant for the Topcon Reference Prism with Hood (monitoring) is -40.0mm. The Leica constant is -5.6mm.
Can I use the Topcon Reference Prism with Hood (monitoring) with a Leica instrument?
Yes, just set the prism constant to -5.6mm.




