



Topcon AT-B4A
- Rapid, stable, durable compensator
- horizontal circle for measurement
- 20cm short minimum focus
- All weather dependability
- Endless fine horizontal adjustments
- Description
- Specifications
Description
The Topcon AT-B4A Automatic Level is a durable and dependable optical leveling instrument designed for everyday surveying, engineering, and construction applications. As the economical model in Topcon’s AT-B series, it combines 24x magnification, reliable automatic compensation, and rugged all-weather construction to deliver accurate and stable leveling performance on demanding job sites.
Equipped with a finely tuned magnetic damping system, the AT-B4A quickly stabilizes the line of sight and helps maintain reliable measurements even when working near heavy equipment, road traffic, or other sources of vibration. Its 20 cm minimum focusing capability is useful when working in confined spaces, while the compact and lightweight design makes the instrument easy to transport and set up in the field.
| Model | AT-B4A |
|---|---|
| Magnification | 24x |
| Objective Aperture | 32mm (1.26in.) |
| Resolving Power | 4″ |
| Field of View | 1°25′ (2.5m / 8.2ft. at 100m) |
| Minimum Focus | 0.2m (7.9in.) from end of telescope; 0.3m (1ft.) from instrument center |
| Image | Erect |
| Stadia Constant | 0 |
| Stadia Ratio | 100 |
| Focusing Knob | 1-speed |
| Sighting Aid | Gun Sight |
| Accuracy (1km Double Run Leveling) | 2.0mm (0.08in.) without micrometer |
| Compensator Type | Pendulum compensator with magnetic damping system |
| Setting Accuracy | 0.5″ |
| Working Range | ±15′ |
| Circular Level Sensitivity | 10′ / 2mm |
| Horizontal Circle Diameter | 99mm (3.9in.) |
| Horizontal Circle Minimum Division | 1° / 1 gon |
| Water Resistance | IPX6 (IEC 60529:2001) |
| Operating Temperature | -20 to +50°C (-4 to +122°F) |
| Width | 122mm (4.8in.) |
| Length | 214mm (8.42in.) |
| Height | 140mm (5.51in.) |
| Weight | 1.5kg (3.3lbs.) |
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