Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable. 中英双语版：英文原文完整保留，中文紧随对应单元；术语采用 v20260916 确认表，自动语义审校结果可追溯。
Optical Spectra With a Diffraction Grating
用衍射光栅观察光学光谱
The goals of this investigation are
Take spectra with simple rotating arm spectrometer
使用简单旋转臂光谱仪取光谱
Produce images of these spectra with a digital imager