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GNAO Design

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Laser Guide Star Facility (LGSF)

The laser guide star facility includes two high-power guide star lasers at 589 nm (from Toptica Project GmbH) producing four side-launched laser guide stars (LGSs). The width of the LGS constellation is adjustable to support the two primary GNAO modes (i.e. the narrow- and wide-field mode). In addition to the lasers, the main components of the LGSF are the Beam Expander and Control Node (BEaCoN) and the laser launch telescpes (LLTs). 

While the BEaCon and laser coolant system are developed in-house, AURA is under contract with Officina Stellare for the design, development and integration of the four LLTs. The LLT optical tube assembly is based on a reverse Galilean telescope configuration used as a 20x beam expander. 

Adaptive Optics Bench (AOB)

The main components of the adaptive optics bench include the wavefront sensors for the laser and natural guide stars as well as a tip-tilt mirror and single deformable mirror to correct the wavefront distortions introduced by the atmosphere. 

The GNAO project completed a one-year competitive design phase for the AOB sub-component. Three teams developed independent conceptual designs for the AOB and each proposed a path toward the final design, build and installation at the telescope. Of the three teams, Macquarie University's Australian Astronomical Optics (AAO) team was selected.

The AOB project is an Australian-French consortium led by Macquarie University's AAO team, in collaboration with the Advanced Instrumentation and Technology Centre (AITC) of the Australian National University, the French Aerospace Laboratory (Office national d'études et de recherches aérospatiales, ONERA), Marseille Astrophysics Laboratory (Laboratoire d’Astrophysique de Marseille, LAM), the Observatoire de Haute Provence (OHP) and French specialist optical manufacturer ALPAO. The partnership also includes consulting firms Space ODT (Portugal), Mersenne Optical Consulting (New Zealand), and Wakea Consulting (France).

System Controller (SysCo)

The system controller is the main software interface between GNAO and its sub-components on the one hand and the operator and Gemini software systems on the other hand. The design is guided by a "one button" philosophy, with the goal to provide an AO facility that is easy to operate in the Gemini queue-scheduled environment. The system controller is being developed in-house.

Real Time Controller (RTC)

The real time controller processes the wavefront sensor data and computes the correction signals that need to be applied to the deformable mirror. AURA is under contract with the National Research Council (NRC) Canada for the design, development, integration, and commissioning of a full RTC template for general purposes and an RTC for GNAO. The real time controller for GNAO is based on the Herzberg Extensible Adaptive Real-Time (HEART) toolkit.

GNAO Design | Gemini Observatory


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