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First light for the Vera Rubin Observatory (VRO) is quickly approaching and the telescope is reaching milestone after milestone. A few weeks ago, the observatory announced that its digital camera, the largest one ever made, is complete. <\/p>\n
Now the observatory has announced that its unique primary\/tertiary mirror has its first reflective coating. <\/p>\n
<\/p>\n The Rubin\u2019s massive digital camera has an important job and garners a lot of attention. But it\u2019s powerless without the telescope\u2019s innovative primary\/tertiary mirror. Primary mirrors are always the most critical and time-consuming part of modern observatories. The VRO\u2019s primary\/tertiary mirror took seven years to make. <\/p>\n The mirror is called a primary\/tertiary mirror because it comprises two optical surfaces with different curvatures. The primary mirror is 8.4 meters, while the tertiary mirror is 5 meters in diameter. The pair of surfaces are combined into one large structure. The unique design reduces the telescope\u2019s engineering complexity without reducing its impressive light-gathering capability. It can be rotated quickly and also settles quickly.<\/p>\n The outer surface forms the primary mirror. It captures light from space first, then that light reflects upwards to the 3.4-meter secondary mirror. After that, it\u2019s reflected back down to the inner 5.0-meter surface that forms the tertiary mirror. Then, the light is sent to the camera.<\/p>\n The primary mirror\u2019s size is critical because it determines how much light the telescope can collect. More light means astronomers can study very faint or distant objects. The VRO\u2019s design allows the camera to capture a large area of sky the size of 7 full moons across in a single image.<\/p>\n