Rubin's 8.4-meter Mirror Reaches the Summit
This morning, a unique astronomical mirror reached its new home in the Andes Mountains of Northern Chile. This incredible mirror will enable Rubin Observatory to catalog an estimated ~40 billion celestial objects—more objects than there are humans on earth. Rubin Observatory will scan the entire visible sky every few nights, visiting each location approximately ~1000 times during its ten-year survey, which is scheduled to begin in 2024. With these fast, repeated observations, Rubin will provide countless new opportunities to do science with transient objects such as asteroids and supernovae. Additionally, with the wide field of view made possible by this mirror, Rubin Observatory will advance the study of dark matter and dark energy.
The 8.4-meter LSST Primary/Tertiary Mirror, one of the largest and most recognizable elements of the telescope, is unusual because it consists of two mirror surfaces combined on one large substrate. Light from the sky will hit the outer ring first, reflect upwards to a separate second mirror, and then bounce back down to the inner ring of the monolith before reaching the telescope. Rubin Observatory's three-mirror design, combined with its highly sensitive camera, allows the telescope to collect light from faint objects over a very large field of view. Combining the primary and tertiary mirrors gives the telescope a more compact shape, which enables it to move (slew) quickly between points on the sky and to settle efficiently before taking its next image.
The 8.4-meter mirror safely arrived at the Rubin Observatory facility on Cerro Pachón in Chile on May 11, 2019. Its eight-week journey began on March 15, 2019, in Tucson, Arizona, USA, where it was fabricated. This mirror was the first Rubin Observatory component to be completed, and it will play a critical role in enabling countless scientific discoveries.