Night Skies Data Report: Photometric Assessment of Night Sky Quality at Wupatki National Monument
Olstad TA , Hung LW, Meyer E . 2025. Night Skies Data Report: Photometric Assessment of Night Sky Quality at Wupatki National Monument. Science Report. NPS/SR—2025/335. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2314782
Abstract This report characterizes night sky conditions in and near Wupatki National Monument (WUPA) using measurements made in the park unit and models of regional conditions based on satellite data. The National Park Service (NPS) Natural Sounds and Night Skies Division (NSNSD) collected ground-based observations and obtained calibrated night sky imagery to characterize the night sky at two sites—Wukoki Pueblo/Ruin in the southeastern portion of the park and Doney Picnic Area in Coconino National Forest, on the Loop Road just outside the park’s southern boundary—on 6 nights between 5/12/2002 and 8/20/2014. Satellite data from 2023 were used to create a map of predicted night sky conditions in and around the park. The sky overhead remains near-pristine with an average zenith brightness of 21.90 magnitudes per arcsecond squared (mag/arcsec2). We estimate more than 94.7% of naked eye stars were visible throughout the data collection period, providing a valuable opportunity to view the natural night sky from the park during a cloudless moonless night. The whole sky over WUPA is just 7–15% (mean = 10%) brighter than average natural levels, indicating excellent dark sky conditions on average. Based on the visibility of astronomical objects, NSNSD classified WUPA’s sky as Bortle Class 2–3 (typical truly dark site to rural sky). The average naked eye limiting magnitude (NELM) is 7, which indicates near-pristine sky brightness levels and exceptional night sky viewing conditions. Our Sky Quality Meter (SQM) measurements averaged 21.77 mag/arcsec2, indicating the zenith is darker than what we can accurately measure with an SQM. The main impacts on WUPA’s night sky quality were the light domes from Flagstaff, Phoenix, and, faintly, Winslow and Tuba City. However, these light domes were contained to within 10° of the horizon. Overhead, the Milky Way had excellent detail.
- Type
- Published Report
- Authors
- Olstad, Tyra; Hung, Li; Meyer, Erik
- Date of Issue
- 2025-07
- Publisher
- National Park Service
- DOI
- 10.36967/2314782
- Units
- NRSS , WUPA
- Keywords
- brightness, light pollution, night skies, night sky, photometric assessment, sky quality