The new Laser Launch Telescopes for Gemini North AO: design and status update

The new Gemini North AO (GNAO) laser guide star facility (LGSF) needs four Laser Launch Telescopes (LLTs) to enable both wide and narrow field corrections using GLAO and LTAO. Early in 2021 Officina Stellare has been awarded a contract to design and build four LLTs. Based on a preliminary LLT design submitted during the call for tender phase, Officina Stellare performed a one-year design study, starting the manufacturing of an engineering and qualification model (EQM) to validate this design and minimize risks on the production of the four deliverable units. Manufacturing of optical and mechanical parts for the EQM is almost completed, including the large aspherical lens, made in-house by CNC optical polishing and tested by high-resolution interferometry. A COTS hexapod provides the active mechanism for a field steering mirror. In-house tests have already validated its performances.