Modern optical theodolites are usually equipped with optical plumb bobs located on the alidade part or on the stand, which are used to center the theodolite over the top of the measured horizontal angle. ...

Autoreduction compensators last 10-15 years are used in many surveying and geodetic devices of new designs. They significantly improve the technology of surveying and measuring works, increase labor productivity and accuracy. ...

Visual axis of levels, common in practice, is set horizontally with a cylindrical level by bringing its bubble in the middle position. Setting the bubble in the zero point takes a lot of time, especially with a high sensitivity of the level, when leveling on unstable soils and in underground workings.

Eyepiece scales are known in surveying practice under the name of Bratgun scales, by whom they were proposed for observing the fluctuations of the plumb line instead of the usual scales installed near the plumb lines. Bratgun's proposal was used for orientation through two shafts, and for this purpose mining theodolites are equipped with an additional eyepiece elbow with an eyepiece scale and reticle. To use the eyepiece scale, the eyepiece tube of the theodolite telescope is replaced with a tube containing an eyepiece scale. The scale is applied mechanically or photographically to the glass. The value of one scale division depends on the focal length of the sighting tube; in mining theodolites it is made equal to about 50″. The high accuracy of the scale markings and the small value of the scale divisions make it possible to use eyepiece scales not only when orienting through two shafts, but also through one. This article proposes a method for using eyepiece scales to solve one of the most important tasks in surveying: the orientation of mine surveys. This method introduces technical improvements in the production of orientation and reduces the time for its execution. The proposed methods of using eyepiece scales increase the speed of orientation, do not require capital and bulky platforms for scales, and allow the observer to make measurements and observations in the mine in better conditions.

The optical vernier is based on the principle of bringing into one plane two diametrically opposite, magnified graduations of the graduated circle. The reading accuracy of an optical vernier is twice as high compared to an ordinary vernier. The eccentricity error is automatically eliminated because diametrically opposite graduations of the graduated circle come into play in the formation of the vernier. A theodolite equipped with an optical vernier can be made in a more compact form than a conventional instrument and is much more convenient to handle, especially for surveying work underground.