Transit Levels: All About Transit Levels

A transit level is a telescope or optical device that is set on a tripod and has a built-in spirit level. Transit levels are mostly used for surveying and construction, but they can also be used to establish the position of lines and other objects concerning one another. Transit laser levels are extremely accurate. In addition to serving as a reference line, they also serve to offer accurate measurements by reading angles.

Transit Level Parts

The transit level has, a tripod base, a tape measure, and a calibrated rod. The transit level itself is divided into several sections:


At the top of the transit level is where the telescope is housed, along with the locking levers. The telescope on a transit level rotates horizontally in a full circle, just like a builder’s level. The horizontal circle contains measures up to 360° and is labeled at each degree. The transit level moves vertically 45 degrees each way, unlike the builder’s level.

There are numerous pieces in the telescope. The telescope’s objective lens is located at the very end. It detects the item being sighted and enlarges it with the assistance of the other lenses inside the telescope.

The eyepiece is located at the other end of the objective lens. The user views through this portion of the telescope.

Crosshairs that run both horizontally and vertically are inside the eyepiece. The eyepiece can be rotated to make the crosshairs more clear and focused. The telescope has a focusing knob that is situated on the barrel. This is done to sharply focus on the object being viewed.

Above and below the horizontal crosshair in the eyepiece are stadia lines, which are brief horizontal lines. The vertical crosshair cuts the stadia lines, giving the user the ability to determine the object’s distance.

Graduated Leveling Vial

The spirit level is another name for the graduated leveling vial. Similar to a typical hand level, the spirit level is used to level the telescope when it is being set up on the base. The leveling vial is positioned above or below the telescope’s barrel. A second spirit level that is incorporated into the base is used to level the transit level’s base in addition to the graded leveling vial that is parallel to the telescope.

Base Plate

The area where the transit level is joined to the tripod is known as the base plate. Each of the three types of base plates has distinct instructions for how to attach instruments to it. It can be fastened on the threaded tripod head when utilizing a threaded instrument base. There is a central bolt on the bottom of the tripod that needs to be screwed into the level whether using a flathead or dome head tripod.


All of the transit level’s upper section is known as the alidade. It is made up of a spindle, a telescope, leveling vials, and a circle-reading tool. Alidade spindle, the instrument’s inner center, is where the alidade is affixed. The verniers and telescope are situated above the spindle.


Vernier scales are used to calculate angular measurements that the primary scale is unable to read. They travel around the main scale. The majority of transit levels include two verniers, which allow for the reading of angles in several directions. Depending on the degree of accuracy required, vernier scales come in a wide variety of graduations.

How To Set Up a Transit Level

  1. Take the level out of its carrying case.
  2. Placing the level on the tripod head directly
  3. The transit level should be screwed or fastened to the tripod base.
  4. The protective lens covers should be taken off and put in the carrying case.
  5. Put the telescope’s sunshade on it.
  6. It’s mounted on your transit level.

How To Use a Transit Level

  1. Before beginning the leveling operation, ensure that the tripod is solid and stable. This step is crucial to complete to prevent the instrument from tipping over while the leveling operation is being done.
  2. Make that the transit level’s connection to the tripod is firmly fastened.
  3. Make sure the leveling base plate is not pressed too tightly on the four leveling screws.
  4. The telescope should be positioned in the first position such that it is immediately over a pair of leveling screws. Set the bubble in the spirit vial’s center using the leveling screws.
  5. As you simultaneously crank both leveling screws in different directions while holding them between your thumb and forefinger, look for movement in the graduated spirit vial.
  6. Thumbs together, move in or out. Following the left thumb, the bubble will move.
  7. When the bubble is in the second position, spin the telescope 90 degrees.
  8. Once the bubble is in the second position and centered, keep doing thumbs in, thumbs out.
  9. Make the necessary modifications to verify that the telescope is still level by turning it back to its initial position.
  10. Check to see if the instrument is level throughout the 360° rotation as you move it through the various stages.

Once the bubble is centered at each position, the final check must be repeated if the instrument is not level at all points. There could harm to the leveling tool if the bubble is still not centered.

How to Focus a Transit Level

Focusing the transit level comes after making sure your instrument is level at all leveling places.

  • Aiming your telescope at an object is the first stage in this procedure. Turning the eyepiece to the left or right should make the thing appear crisper even if it should first appear hazy.
  • Point the telescope directly at the desired target after eyepiece focusing. Use the focusing knob to sharpen the target item while maintaining focus in the crosshairs. A sight line that has been established using the telescope is known as a level grade line or reference line. It takes two employees to establish and is formed at the horizontal crosshair.

With the information above, you can start using your transit laser level rightly!