Adaptive optics for night astronomy

Ever since adaptive optics was first utilized in 1989 in ground-based astronomy to achieve diffraction-limited observation, adaptive optics systems have gradually become must-have instruments for large ground-based astronomical telescopes. Due to the increasingly stringent requirements for scientific instruments used for night astronomy observation, and to improve compatibility, over the last 20 years adaptive optics has undergone continuous and rapid development. Many new schemes have emerged, for instance, laser guide star adaptive optics, multi-conjugate adaptive optics, extreme adaptive optics, and ground layer adaptive optics. However, even though their performance is improving, there are still many limitations. In this article we analyze systems that are already in use, and discuss the advancement of several new systems specifically designed for night astronomy applications.