A laser transit is a type of solid-line laser mounted in a set location. The laser used by these devices is visible in the air, which makes for easy tracking. These devices are used in surveying and construction to create an easily-identifiable, but non-permanent, line. The laser transit was first used as a surveying tool—it was mounted onto a standard survey scope to provide a visual indication of the scope’s tracked line. This tool has since branched into other applications, such as construction and home repair, where it is commonly called a laser-line level.
Transits are common in many fields of science and engineering. Each of these devices has specific functions, but they all have one thing in common. Transits allow measurement or observation of very specific slices or areas of space. Typically, they are mounted or held in some way which allows a user to specifically designate the observed area. For instance, a transit telescope observes astronomical bodies as they move past a specific plane.
The first major use of a laser transit was as part of a surveying scope. When a surveyor plots out distance and direction, he uses a very specialized type of telescope. Generally, one scope sits at a fixed location and looks at the next scope, which looks at the next scope, and so on. Each one gives highly-detailed direction and distance information to the surveyor.
By attaching a laser transit to the system, it is possible for a surveyor to create a visible line from one spot to another. This allows for increased accuracy and precision during the survey. When teams of surveyors work together, this allows one member to easily see what another is looking at. This way, the teams can work together more easily to finish large projects.
This technology has moved into the world of construction and repair. During construction, a common laser transit helps builders line up edges and walls with set points. This both speeds up initial construction and assures builders that the structure is exactly where it is supposed to be. The only major difference between this and a surveyor’s transit is the lack of the scope.
With the exception of the laser used, personal laser-line levels are very similar to a transit. These devices send out a fan-shaped invisible laser that blankets a small plane. When it shines on an object, the laser becomes visible. The level itself will generally fix to a wall or other surface, creating a stationary transit-like effect.