optical plummet

optical plummet

A device on some transits and theodolites; used to center the instrument over a point, in place of a plumb bob, which moves in a strong wind.
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The NETH503 5" Theodolite has a 30x telescope with illumination, 360 degree full transit, digital reading of both horizontal and vertical angles, dual-side LCD display, photoelectric incremental encoder, optical plummet, alkaline or rechargeable battery pack selectable.
Instruments are centered over the vertex by suspending a plumb bob beneath the instrument or by using an optical plummet. For accurate surveys, the plumb bob suspended beneath the instrument or the optical plummet must be aligned with a surveyors nail in a stake or a surveyors nail driven into an asphalt or concrete surface.
Procedures for Centering an Instrument The procedures for centering an instrument over a point will vary depending on whether the instrument uses a plumb bob or an optical plummet. A common feature of instruments that are designed to measure horizontal angles is the ability to make a slight lateral movement after the instrument is mounted on the tripod.
TIP Although the optical plummet will be used to center the instrument, a plumb bob can be used to center the tripod.
The last step is to secure the instrument, level it with the spirit level mounted on the instrument and check the optical plummet. If the instrument is not centered, it is loosened and centered again.
Tenders are invited for Standard Vernier Theodolite - One Set Consisting Of Following Specification: Accuracy 20 Seconds, Erect Image Using Prisms, Optical Plummet System Embeded In Circle, Dark Blue Coated Lenses, Steel Axis With Ball Bearings, Circles Made From Steel, Carrying Case.
Tenders are invited for supply of hardware and chemical items-Dual ferquency globle navigational satellite system -DUAL FREQUENCY GNSS Receiver with in-built software and Software for data processing,GNSS Antenna,Antenna Cables along with Cable Caps,Height Measuring Device,Standard Battery Set (one set is of two battery),Charger (240V AC-50Hz),Tribarach with optical plummet,Tribrach adaptor,Spare power cable with caps,Operator manual for DUAL FREQUEY GNSS,Transport cases,Telescopic Tripod,Tripod Bag,Standard Tool kit,Carry case with shoulder strip for DUAL FREQUENCY GNSS,GNSS processing software,Controller
Tenders are invited for Standard Vernier Theodolite Model No St-20E Cat No.Lm10106 Having Accuracy 20 Second With Erect Image Using Prism Dark Blue Coated Lenses Optical Plummet System Embrdded In A Circle Of Pure Silver Steel Axis With Ball Bearing And Fibre Glass Carrying Case And Alluminium Triped Stand With Standard Accessories.
- (1) Heavy duty Tribrach with optical plummet and adjustable circular level vial.
Tenders are invited for Procurement of DGPS Instruments (Receiver with internal memory or SD Card 2GB or more, Aluminium Telescopic Tripod, Tribrach, Height Adopter with optical Plummet, Rechargeable Batteries, Quick Charger, Carrying Case, Post Processing Software in Computer ) for the Modern Survey Work.
For high-accuracy work, the RFP should always specify that the optical plummets and bubble levels of the tribrachs, which hold the antennas on the tripods, be checked before and after each day of observations to ensure proper calibration.

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