sci19005 — Announcement
Kitt Peak 4m Mayall Back in Action
May 18, 2019
Arjun Dey, NOAO
After a 14-month hiatus, the Mayall 4m telescope is refurbished and back in action as it prepares for the installation of the Dark Energy Spectroscopic Instrument (DESI).
The Mayall was closed temporarily in February 2018 in order to install the new corrector that will deliver a corrected 3-degree diameter field for the DESI focal plane. The telescope now has a new top ring supporting a new 5-ton corrector barrel, which is controlled by a hexapod. The hexapod provides focus motion and tip/tilt correction to optimize image quality.
The overhauled Mayall achieved “first light” on 1 April 2019 with an imaging camera (the “Commissioning Instrument”). The DESI team is currently testing the optical and mechanical performance of the telescope and understanding the issues associated with target acquisition and guiding to the accuracy and precision required for DESI.
Some images from DESI construction, installation and first light. Hover your mouse over the image to pause the slideshow. Click the image to step through a larger version of the slideshow with captions.
The Commissioning Instrument campaign will continue through mid-May, after which the installation of the DESI focal plane will begin. The ten DESI focal plane segments, each of which holds 500 robotic fiber positioners, will begin arriving on Kitt Peak next month and will be mounted behind the corrector over the summer. Three of the ten DESI spectrographs have already been installed in the thermally controlled “shack” in the old Mayall Coudé room, and the remainder are on schedule.
On-sky commissioning of DESI will begin in September 2019, followed by a “Survey Validation” phase during which the DESI team will test the system’s ability to deliver redshifts for the faint DESI targets at sufficient completeness and reliability.
The DESI target lists are also in the process of being finalized. The DESI Legacy Imaging Surveys, which were conducted to generate these target lists, have now completed their data collection phase. The next data release (DR8) of the Legacy Imaging Surveys will cover more than 14,000 deg2 of the extragalactic sky (at Galactic latitude |b| > 15) in the g, r and z bands and will be available publicly by June 2019.
At Kitt Peak, we are looking forward to an exciting new adventure with the venerable Mayall! For more details about DESI and first light, see https://newscenter.lbl.gov/2019/04/03/dark-energy-instruments-lenses-see-night-sky-first-time/
DESI is supported by the US Department of Energy’s Office of Science; the US National Science Foundation, Division of Astronomical Sciences under contract to the National Optical Astronomy Observatory; the Science and Technology Facilities Council of the United Kingdom; the French Alternative Energies and Atomic Energy Commission (CEA); the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the National Council of Science and Technology of Mexico; the Ministry of Economy of Spain; and DESI member institutions. The DESI scientists are honored to be permitted to conduct astronomical research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation. View the full list of DESI collaborating institutions, and learn more about DESI here: desi.lbl.gov.
