peg adjustment—A method of adjusting a leveling instrument of the dumpy-level type to make the line of collimation parallel with the as the spirit level, using two stable marks (pegs) the length of one instrument sight apart. The peg adjustment can be used with a wye level, but sin 11 an instrument is more readily adjusted by reversing the telescope in it’s wyes. A form of peg adjustment is used in determining the collimation error of first-order leveling instruments of the dumpy-level type.

–

Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

Part of LearnCST’s exam text bundle.