It is also termed as line of sight and is defined as an imaginary line joining the point of intersection of cross-hairs of the diaphragm and the optical centre of the object glass and its continuation.įigure 3: Line of collimation 8)Axis of Telescope: It is done by completely transiting the telescope and then swinging the telescope.
![rotate plants upside down in lumion 8 rotate plants upside down in lumion 8](https://images-na.ssl-images-amazon.com/images/I/410AsdU3ZIL._SL160_.jpg)
It is the process of transition of vertical circle from left to right or vice versa. Similarly, when the vertical circle is present on the right side of the observer, it is known as face right and the observations are termed as face right readings. While taking observations, if the vertical circle of the instrument is on left side of the observer, the instrument is said to face left and the readings taken in this position are known as face left readings. It is the process of rotating the telescope of the theodolite 180° about the vertical axis in horizontal plane. It is also known as plunging or reversing. It means to bring the telescope upside down for pointing in opposite direction by 180° revolution of the telescope about horizontal axis in vertical plane. It is the process of setting theodolite exactly over the station using a plumb bob. The following terms should be remembered while dealing with a transit theodolite 1)Centering: Micrometer theodolite is that type of theodolite in which micrometer is provided for reading out graduated circle. Vernier theodolite is the type of theodolite in which the graduated circle is read with the help of Vernier. This type of theodolite is obsolete now.įigure 2: Non-transit theodolite. If the telescope of a theodolite cannot be revolved about the trunnion axis, it is known as a non-transit theodolite.
![rotate plants upside down in lumion 8 rotate plants upside down in lumion 8](https://i.ytimg.com/vi/RIGvh6Y9DKM/maxresdefault.jpg)
This type of theodolite is commonly used for surveying. If line of sight of the telescope can be reversed through the rotation of telescope by 180° about the trunnion axis in vertical plane, the theodolite is known as transit theodolite. There are basically two classifications of theodolite 1)Transit Theodolite: It is considered to be more precise and speedy than the regular chain survey, compass or plane-table surveying and is commonly used in engineering fields for land surveying, route surveying and constructional surveys. It can completely rotate along the horizontal plane and its telescope can be rotated up to 180°. In survey, a theodolite is an instrument mounted with a moveable telescope, used for precise measurements of horizontal and vertical angles.