Letters of Intent received in 2019

LoI 2021-2098
Towards a World Standard for Dark and Quiet Sky Protection

Date: 16 August 2021 to 18 August 2021
Location: Busan, Korea, Rep of
Contact: Constance Walker (cwalker@noao.edu)
Coordinating division: Division B Facilities, Technologies and Data Science
Other divisions: Division B Facilities, Technologies and Data Science
Division C Education, Outreach and Heritage
Co-Chairs of SOC: Constance Walker (NOAO)
Richard Green (University of Arizona)
Narae Hwang (KASI)
Claudio Melo (ESO)
Sarah Pearce (CSIRO)
Co-Chairs of LOC: David Galadi-Enriquez (Calar Alto)
Harvey Liszt (NRAO)
James Lowenthal (Smith College)
Ramotholo Sefako (SAAO)
Diane Turnshek (Carnegie Mellon U.)



Optical/Infrared (nighttime) Observatories: limiting observations, monitoring over time, simulating light pollution over mid- to long-time scales, history of light pollution (Asiago Observatory, Mt Wilson, etc.), impact of diffuse and streaked artificial sky glow, local regulations and their effectiveness
* Overview: LED revolution, orbital constellations
* Highest Entendue: LSST, LAMOST, PanSTARRS, DECam, DESI
* Largest apertures: VLT/EELT, Maunakea Telescopes, SALT, Hobby-Eberly, GTC
* Dark and Active Sites: Lowell Obs., Palomar, Calar Alto, Ali Tibet, Ladakh, Uzbekistan, etc.

Radio Observatories: critical observing frequencies; impact of terrestrial stationary and moving interferers; orbital sources of RFI; progress on regulation; radio quiet zones; dynamic spectrum coordination zones; out-of-band observing
* Overview
* Protected environment for observatories: SKA mid and low (includiing AKSAP, MWA and MeerKAT), FAST, VLA/ngVLA, ALMA, Green Bank, IRAM, Arecibo, Maunakea, Antarctica, Arizona

Dark Sky Preserves
* By continent: usage, protection, effectiveness of regulation

Urban Sky Glow
* Measurement campaigns, trends (intensity, color), and cross-calibration
* Local regulations, alliances non-astronomical interests
* Communication strategies to promote dark skies protection among diverse stakeholders (e.g., public, government, business, etc.)

UNCOPUOS Model Regulations
* Summary of content and progress
* Prospects for local adoption
* Needs for global and local modification



The rapidly changing technological environment for solid-state outdoor lighting and radio-frequency communications creates ever more pressing needs for protection of professional observatory sites and measures to preserve night sky access for the public at large. This proposal is for a working Focus Meeting, made in the context of the launch of constellations of small satellites in low Earth orbits with high impact on both optical and radio observations. The goal is to work toward a set of globally applicable standards to protect a dark and quiet sky over professional observing sites and protected natural areas, and to share approaches for night sky access for the world’s rapidly urbanizing population in general. This Focus Meeting is assumed to follow an international workshop to develop standards to recommend to the UN Commission on the Peaceful Uses of Outer Space (UN COPUOS), linking the essential nature of ground-based observing to the support of space assets.

The LED revolution continues to change the basic nature of outdoor lighting. Even sympathetic regulatory bodies request assessment of current levels and potential change of artificial sky glow before revising protective regulation for observing sites and natural areas. A major outcome of the meeting will be the reporting of measurements and trends (in intensity and spectral composition) for artificial sky glow for sites around the globe, both diffuse from ground-based sources and streaks from orbital constellations. Another important outcome will be the collection of the diversity of local/regional regulation and an assessment of the effectiveness of the framework as well as the enforcement.

Unlike optical astronomy, radio frequency usage has commercial value and is regulated nationally and internationally. One purpose of this session is to promote a wider understanding of the complex regulatory framework and its current issues, and to share information about the conditions at the major radio observatories around the world.

Radio astronomy sites and radio astronomy frequencies alike are increasingly affected by the exploding commercial effort toward terrestrial mobile and satellite broadband communications, vehicular radars, the “Internet of Things”, etc. The meeting will explore emerging conditions that will affect radio astronomy access to the spectrum in the near future, in order to lay the groundwork for dealing with changing observing conditions in an increasingly congested spectrum.

The international right to starlight as promulgated in IAU Resolution 2009-B5 becomes more and more challenging as urban sky glow becomes stronger, bluer and more pervasive. This section will report time-series citizen science and professional measurements of global artificial sky glow and the impacts of local regulations on curbing that glow. Strategic planning will explore alliances in support of dark skies with groups supporting other issues such as natural preservation, energy sustainability, and human health.

At this time, there are preliminary plans for an international workshop in the first half of 2020 to define a set of site protection standards to recommend to UN COPUOS. In principle, those standards for regulation of optical artificial sky glow should be firmly based on effective local regulations, of the kind to be described in this Focus Meeting. In practice, there may be useful local examples that were not fully considered or required modifications to meet local circumstances. This session, with its presentations and discussion, will aim toward a basic global approach to site protection with an accompanying understanding of variants required for local conditions. Avenues for input to control of optical and radio impacts of orbiting smallsat constellations on professional observatories both inside and outside the country of origin will be seriously explored.

The contents of the Focus Meeting will serve as the input for Commission C.B7 to develop its action plan for the coming triennium, including laying the groundwork for global adoption of standard guidelines, adapted for local site protection circumstances.


Two of the SOC chairs (R. Green, C. Walker) have organized the 2.5 day Focus Meetings in 2012 and 2015 and a 2 day offsite meeting during the IAU GA in 2018. We are proposing for a 2.5 day Focus Meeting anytime during the week of August 16th or August 23rd. For instance it could be continuous over 3 days or half days over 5 days.

Due to the limited spaces to list the SOC chairs/members on the LOI form, the list of LOC chairs are actually confirmed SOC members. In addition to the confirmed SOC chairs/members, we are awaiting confirmation from Yongheng Zhao (LAMOST, China).

Division presidents of B and C have been informed of this Letter of Intent and our plan to invite Commissions B4 (Radio Astronomy) and C4 (World Heritage) to sponsor the session, if it goes forward.