Description
The Topcon ATP1 360° Prism (with protective cover) is a 360° prism made by Topcon and also sold under the Sokkia brand (part number 210150005 (Sokkia US: 210150005-SURSK)).
Its absolute prism constant is -7.0 mm, which is +27.4 mm on the Leica scale.
Specifications
| Model: | ATP1 |
| Manufacturer: | Topcon |
| MPN: | 210150005 (Sokkia US: 210150005-SURSK) |
| Status: | Current |
| Height Offset: | 87.0 mm |
| Absolute constant: | -7.00 mm |
| Leica constant: | +27.40 mm |
| Constant source: | Manufacturer documentation |
| Weight: | 265 g |
| Centring accuracy: | ±3.0 mm |
| Maximum range: | 1,000 m (1.3 to 1,000 m (GT-1200/600 and GT-1500/700 datasheets); 'up to 1000 m' with no haze, visibility >20 km, slightly overcast, no scintillation (monitoring prisms datasheet)) |
| ATR / tracking range: | 600 m |
| Mount: | 5/8" Thread |
| Coating: | Silver |
| Equivalents: | Builder Series 360 Prism (1004684-01); Sokkia ATP1; aftermarket 'ATP1-style' prisms |
| Last verified: | 21/10/2026 |
Sources
Topcon ATP1 360° Prism (with protective cover) FAQ
Below is a list of frequently asked questions about Topcon ATP1 360° Prism (with protective cover).
What is the prism constant for the Topcon ATP1 360° Prism (with protective cover)?
The absolute prism constant for the Topcon ATP1 360° Prism (with protective cover) is -7.0mm. The Leica constant is 27.4mm.
Can I use the Topcon ATP1 360° Prism (with protective cover) with a Leica instrument?
Yes, just set the prism constant to 27.4mm.
What is the height offset of the Topcon ATP1 360° Prism (with protective cover)?
The height offset is 87.0mm.
