Update on Sacramento Peak Observatory — NSF Dunn Solar Telescope
The U.S. National Science Foundation (NSF) and the USDA Forest Service are providing this update on the status of the Dunn Solar Telescope (DST) at Sacramento Peak Observatory in Sunspot, New Mexico, on the Lincoln National Forest.
Mercury Drainage Complete
Between July 23 and August 1, 2026, NSF completed the drainage of liquid mercury from the Dunn Solar Telescope in compliance with all applicable federal and state environmental requirements. NSF is working closely with the New Mexico Environment Department on regulatory requirements and will continue to collaborate with state and federal partners on the remediation of mercury within the telescope.
Status of the Dunn Solar Telescope Structure
Based on expert analysis, NSF has determined that mercury amalgamation, a condition in which mercury bonds to metal surfaces, is present throughout the telescope's interior vacuum structure. Fully assessing and remediating this contamination requires access to the interior of the structure, which requires opening the telescope system and removing the central vacuum tube. NSF's engineering and hazardous materials contractors have assessed that complete demolition of the Dunn Solar Telescope is the safest and most efficient path to full remediation consistent with NSF's obligations.
To inform the demolition process, NSF will conduct a comprehensive regulated materials assessment of the DST prior to demolition, in collaboration with the New Mexico Environment Department. This assessment will address hazardous materials, including mercury, lead, and asbestos. Testing for mercury vapor condensation in the concrete will also be conducted.
NSF's goal, consistent with its long-standing agreement with the Forest Service, is to fully remediate the site and leave it as clean as possible.
Education and Historic Preservation
NSF is committed to honoring the educational and scientific legacy of Sacramento Peak Observatory. As part of NSF's programmatic agreement with the Forest Service and the State of New Mexico, NSF has committed up to $100,000 to support an interpretive exhibit and/or signage that will help preserve the history of the observatory and its contributions to solar science for future generations. NSF looks forward to working with the community and its partners to bring that commitment to life.
Future Use of the Site
As NSF completes full remediation of the observatory footprint, the Forest Service will continue to explore potential future opportunities that create public value and honor the site’s long-standing legacy. As ideas begin to take shape, the Lincoln National Forest plans to engage local partners and interested stakeholders to better understand community priorities and interests.
Community organizations or individuals who would like to stay informed about future discussions are welcome to contact the Lincoln National Forest at ReImagineSunspotNM@usda.gov.
NSF and the Forest Service will continue to provide updates as the remediation process moves forward.