System performance of the laser projection system (LPS) for the ELT

Abstract

Presently TNO/Demcon are manufacturing nine Laser Projection Systems (LPS). TNO is responsible for the design and manufacturing of the Optical Tube Assembly (OTA), the baseplate and the LPS cover. Demcon designed and manufactured the Beam Conditioning and Diagnostic System (BCDS). TNO is also responsible for the system performance and its verification tests. Six units will be used on the ELT. The other three are destined for the VLT. That will allow the operation of the adaptive mirrors enabling unprecedented image quality of the telescopes. The design of this system is based on the four laser guide stars units as used on the VLT. The system has been upgraded considerably compared to the units used for the VLT. Its FOV has increased to 7 arcmin (half cone). The laser power goes up to 50W and the BCDS has been completely redesigned. The BCDS is located between the laser source and the OTA that produces the Ø300 mm output beam. Maintainability and accessibility of the system have also been much improved. Prime qualities are its insensitivity to temperature changes (static and dynamic), its accuracy and its FOV. Assembly of the first unit is finished and in January the acceptance testing of the system started. The first unit is expected to be delivered to ESO in autumn 2024.