Gemini South's primary mirror and telescope structure

图注： This is the primary mirror and supporting structure of a large optical telescope at the Gemini South Observatory in Chile. The primary mirror is the largest and most important mirror in a reflecting telescope: its gently curved surface gathers light from faint stars, galaxies, and nebulae and reflects that light to a focal point. At this focal point light is either fed directly in to an instrument to record spectra and images or redirected to such an instrument by a series of further mirrors. The sturdy metal framework around the primary mirros keeps the mirror precisely aligned and protected while the telescope moves to track objects across the sky. In telescopes that use mirrors instead of lenses, such as this one, the mirror is what collects and focuses the light from distant celestial objects. Larger mirrors can capture more light, allowing astronomers to see fainter and more distant objects. A larger primary mirror can also take sharper images of the sky, but this is often negated by the blurring effect of the Earth's atmopshere. A primary mirror must be perfectly smooth to tolerances of fractions of a wavelength of light so that it produces sharp, clear images. We can think of the primary mirror as the “eye” of the telescope that looks out into space, with its shape and support enabling powerful astronomical observations.
来源： International Gemini Observatory/NOIRLab/NSF/AURA/M. Paredes 来源链接

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