Teodolit
theodolite (/θiːˈɒdəlaɪt/) adalah instrumen presisi untuk mengukur sudut di bidang horisontal dan vertikal. Theodolites terutama digunakan untuk survei aplikasi, dan telah diadaptasi untuk tujuan khusus dalam bidang-bidang seperti metrologi dan teknologi peluncuran roket. Sebuah teodolit modern terdiri dari teleskop bergerak dipasang dalam dua tegak lurus sumbu-horizontal atau trunnion sumbu, dan sumbu vertikal. Ketika teleskop yang menunjuk pada objek target, sudut masing-masing sumbu dapat diukur dengan presisi yang besar, biasanya untuk detik busur.
Transit refers to a specialized type of theodolite developed in the early 19th century. It featured a telescope that could "flip over" ("transit the scope") to allow easy back-sighting and doubling of angles for error reduction. Some transit instruments were capable of reading angles directly to thirty seconds. In the middle of the 20th century, "transit" came to refer to a simple form of theodolite with less precision, lacking features such as scale magnification and micrometers. Although precise electronic theodolites have become widespread tools, the transit still finds use as a lightweight tool on construction sites. Furthermore, the Brunton Pocket Transit, commonly employed for field measurements by geologists and archaeologists, has been in continuous use since 1894. Some types of transits do not measure vertical angles.
The builder's level is often mistaken for a transit, but it measures neither horizontal nor vertical angles. It uses a spirit level to set a telescope level to define a line of sight along a level plane.