Rubin’s 8.4-meter Mirror Moves into the Observatory
Rubin’s 8.4-meter combined primary/tertiary mirror has been moved to the maintenance floor inside the observatory for the very first time. With this move, the mirror is officially “home” inside the main observatory building, where it will remain for the rest of construction and throughout Rubin’s ten-year survey. The mirror — which hasn’t been coated yet and is still a glass blank — arrived on Cerro Pachón in May 2019 and has been stored in a building outside the observatory since then. It’s been safely packed in a transport/storage box the whole time to protect it from damage, and on March 7th the summit team loaded that box onto a specialized truck to make the short (~ 600 m / 656 yd) but important journey from the storage building to the observatory.
This exciting move was actually the second major move on the summit during the past week. The transport team first had to move the 8.4-meter steel stand-in mirror out of the observatory to make room for the glass mirror. The successful transport of the steel surrogate mirror on March 6th provided a test-run — approximately in reverse — for the glass mirror move the next day.
Both moves were carried out with Javier Cortés, the same company that transported the mirror to the summit from the shipping dock in Coquimbo after it arrived in Chile in mid-2019. Rubin’s Summit Safety team also played a major role in both days’ events, ensuring that all safety regulations were followed and that all staff involved had completed the appropriate training and preparation.
Although the mirror moves were completed in just two days, many months of planning and weeks of site preparation were necessary to ensure a smooth ride between the two buildings — especially for the delicate glass mirror. Some extra strategizing was also necessary to fit the mirror box onto the crowded observatory maintenance floor — the mirror’s steel support structure had to be moved temporarily into the vertical platform lift (aka the equipment elevator) to make room. Rubin staff members onsite likened it to playing Tetris with some really big and oddly shaped blocks!
Now that it has arrived safely inside the observatory, the mirror will be removed from its storage box — using a custom-made vacuum lifting fixture — and prepared for coating in Rubin’s onsite coating chamber. Check back for news and images of the mirror coating process in a few weeks.