A secondary mirror of a radio or infrared telescope mounted in such a way that it can be vibrated so as to switch the telescope beam rapidly between two positions on the sky in a similar manner to a chopper.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。