SMART: Special-shaped Micro-lens Aimer for Real-time Targeting of multi-object telescopes

¹ Key Laboratory of In-Fiber Integrated Optics of Ministry of Education, College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, PR China
e-mail: sunweimin@hrbeu.edu.cn
² Key Laboratory of Photonic Materials and Devices Physics for Oceanic Applications, Ministry of Industry and Information Technology of China, College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin 150001, PR China
³ Qingdao Innovation and Development Center of Harbin Engineering University, Qingdao 266000, PR China
⁴ Yantai Research Institute and Graduate School of Harbin Engineering University, Yantai 264000, PR China
⁵ State Key Laboratory of Aerodynamics, China Aerodynamics Research and Development Center, Mianyang 621000, PR China

Received: 22 October 2023
Accepted: 8 February 2024

Abstract

In the process of acquiring astronomical spectral data, the alignment accuracy between the fiber core in the focal plane and the image of the target star is crucial for multi-target telescopes. This work presents a Special-shaped Micro-lens Aimer for Real-time Targeting (SMART), which combines a special-shaped microlens and a fiber bundle to carry out online alignments and improve the injection efficiency of the fiber. The special-shaped microlens consists of a central plate and six side microlenses. The central plate transfers the signal to the science fiber without focal ratio degradation. The side microlenses focus the leakage light to the feedback fibers and return a misalignment signal. The experiment in the laboratory indicates that the SMART-T system can visually demonstrate the recognition of offsets. The SMART-P system is able to realize the alignment for a variety of seeing cases. Under the condition that the diameter of turbulent star image is 0.2 mm, the corrected injection efficiency is improved to 99.7% of the best injection efficiency of the science fiber. The re-centering accuracy is 0.01 mm.