ARGOS: the laser guide star system for the LBT

ARGOS is the Laser Guide Star adaptive optics system for the Large Binocular Telescope. Aiming for a wide field adaptive optics correction, ARGOS will equip both sides of LBT with a multi laser beacon system and corresponding wavefront sensors, driving LBT's adaptive secondary mirrors. Utilizing high power pulsed green lasers the artificial beacons are generated via Rayleigh scattering in earth's atmosphere. ARGOS will project a set of three guide stars above each of LBT's mirrors in a wide constellation. The returning scattered light, sensitive particular to the turbulence close to ground, is detected in a gated wavefront sensor system. Measuring and correcting the ground layers of the optical distortions enables ARGOS to achieve a correction over a very wide field of view. Taking advantage of this wide field correction, the science that can be done with the multi object spectrographs LUCIFER will be boosted by higher spatial resolution and strongly enhanced flux for spectroscopy. Apart from the wide field correction ARGOS delivers in its ground layer mode, we foresee a diffraction limited operation with a hybrid Sodium laser Rayleigh beacon combination.

ARGOS是大型双筒望远镜的激光导星自适应光学系统。为了实现大视场自适应光学校正，ARGOS将为大型双筒望远镜（LBT）的两侧配备多激光信标系统和相应的波前传感器，驱动LBT的自适应副镜。利用高功率脉冲绿激光，人造信标通过地球大气层中的瑞利散射产生。ARGOS将在LBT的每个镜子上方以一个较大的星座布局投射一组三颗导星。返回的散射光对靠近地面的湍流特别敏感，在选通波前传感器系统中被检测到。对光学畸变的地面层进行测量和校正使ARGOS能够在非常大的视场上实现校正。利用这种大视场校正，多目标光谱仪LUCIFER所能进行的科学研究将因更高的空间分辨率和光谱学通量的大幅提高而得到推动。除了在其地面层模式下提供的大视场校正外，我们还预见了一种结合钠激光和瑞利信标的混合模式下的衍射受限操作。