Sensing the Luminous Night: Capturing and communicating time-based observations of environmental light across urban and rural sites

Rupert Griffiths1[0000-0003-3558-8484]

1 University of Lancaster, Lancaster, UK

Abstract. This paper attends to the boundary between the human and the non-human in urban space. It considers the role that light plays in choreographing human and non-human behaviours and how this can be used to situate individuals in spatiotemporal imaginaries that extend from the local to the planetary. The research designed and installed environmental light sensors and Internet of Things infrastructure in two sites—one rural and one urban—to capture the temporal patterns of natural and artificial light. The observations collected were used to create timepieces that reflect diurnal, circalunar, and seasonal cycles. This hybrid approach to timekeeping harmonizes human time standards with ecological and planetary rhythms and promotes an awareness of the environmental impact of artificial light at night and a broader environmental consciousness. Interdisciplinary methods were used, drawing from the geohumanities, time studies, night studies, design, electronic engineering, and creative practices to foster a connection between people and their surroundings and encourage stewardship toward urban and natural environments. Participatory workshops demonstrated how localized, sensor-driven art installations can influence public perceptions and behaviours regarding artificial light and its ecological consequences.

Keywords: Urban nature, time studies, artificial light at night.

Towards Cosmocentric Urban Imaginaries

Urban imaginaries play a significant role in shaping societies and citizens, influencing how cities are perceived, experienced, and constructed. Examples such as the Garden City Movement, Modernist Urban Planning, Megacities, Sustainable Cities, Smart Cities, and emerging New Urban Agendas have found expression in many places, including Letchworth Garden City (UK), the Barbican (UK), the JingJinJi zone (China), Songdu (South Korea), and Chengdu's Tianfu District Great City (China), respectively. This trajectory, from the nineteenth century to the present day, demonstrates a movement from predominantly spatial forms of planning to increasingly sophisticated spatiotemporal approaches to urban design, facilitated by technology, economic development, population movements, and environmental concerns. This trajectory also belies a movement from anthropocentric urban design that sees the city as defining and delimiting nature towards ecocentric approaches that integrate ecological principles into urban environments, emphasising harmony with nature, sustainability, biodiversity, and the well-being of all forms of life—a transition from the spatially and socially deterministic approaches of the Garden City Movement and Modernism to the spatiotemporal metabolism of smart cities and ecocentric and ecological urbanism (e.g., [1][2]).

Meanwhile, human-driven climate change, environmental degradation, and biodiversity loss create an awareness that cities are situated in spatial and temporal scales that extend far beyond the urban fabric [3]. The entwinement of human activity with solar radiation and atmospheric and oceanic processes moves us from ecocentric to cosmocentric and cosmopolitical concepts that acknowledge the interconnectedness and agency of all life and matter at scales extending far beyond those usually considered in urban design—from earth systems to evolutionary, geological, planetary, and cosmological spatiotemporal scales (see [4][5]). Examples include Indigenous Urbanism, which respects and embodies these relationships and recognizes the need to consider the rights and agencies of multiple species and natural entities, such as rivers [6][7], in urban planning and governance.

Reimagining Smart City Infrastructure

This paper considers how smart city infrastructures might be deployed to contribute to a spatiotemporal consciousness among citizens that encompasses the local and planetary processes that are becoming increasingly relevant to how urban futures are imagined and enacted. Smart city platforms typically consist of a layer of diverse sensors that collect information that inform algorithmic decisions regarding infrastructures, services, and users [8, 9, 10]. Common critiques of smart cities cite incompatibility with the informality of cities, the importance placed on economics and corporate actors, the reproduction of social and economic inequalities [11], and an understanding of cities as primarily spatial entities with little consideration of how smart city infrastructure remodulates the temporality of cities [12].

Although the smart city model of control and governance has demonstrated both success and failure in delivering efficiencies in infrastructure and services [13], it could also be seen as an opportunity to approach data itself as a cultural artifact capable of inflecting imaginaries beyond those associated with efficiency and optimization (or conversely, inequality and failure).

This paper discusses prototypes that use data related to natural and artificial light collected through smart city infrastructure as the source material for cosmocentric imaginaries that situate the daily life of citizens within local and planetary cycles, rhythms, and processes. This approach uses technological smart-city sensors and infrastructures to augment urban control and governance with imaginaries that may encourage citizen participation and stewardship, where urban environments serve human needs, while being responsibly embedded and positively contributing to local and planetary ecologies and ecosystems.

Urban and Rural Night Case Study

Two complimentary pilot projects were undertaken—the first was installed in 2021 in Leighton Moss RSPB Nature Reserve in the Northwest of England and the second in 2023 in Bonn Botanische Gärten in Germany in collaboration with the University of Bonn Institute for Science and Ethics [14].

The rhythms of natural light are of great importance, choreographing the biologies and behaviours of almost all life on earth. Artificial light adds noise to the night-time environment, disrupting the circadian rhythms and behaviours of organisms and the ecologies to which they belong. Artificial light at night is increasingly prevalent in both urban and rural environments [15]. It affects the visual quality of the night and our capacity to experience it as ‘a time and place in its own right’ [16]. It has deleterious effects on the health, well-being and ecologies of humans and non-humans [17][18][19][20]. Although its significance is well documented, artificial light at night is often considered benign and untroubling. The night is often overlooked, and formal control of lighting is uncommon. Addressing artificial light at night thus relies on engagement, awareness, and education.

Methodology and Methods

The sensors and visualizations discussed here were developed in response to the above concerns. Taking an interdisciplinary approach that draws from the geohumanities, night studies, time studies, design, electronic engineering, and creative practices, the project observes the environment using various light sensors and communicates observations through time-based electronic artworks, referred to as LightClocks [21]. The process augments a human time standard (Linux Time) with environmental information related to the movement of the earth on its axis and around the sun and the movement of the moon around the earth. Internet of Things (IoT) infrastructure, unattended environmental sensors, and visualisations were used to situate the sites in multiple spatiotemporal scales—particularly, the diurnal, circalunar, and seasonal scales that are driven by the rotation of the earth and its movement around the sun and the moon’s orbit around the earth. This situates citizens in both local and cosmocentric temporal imaginaries related to cycles and rhythms of natural and artificial light. The sensors and visualisations were designed to engage people in discourse regarding the roles and effects that natural and artificial light have upon organisms and ecologies. To achieve this, careful consideration was given to the selection of sites and IoT infrastructure and the development of sensors, housings, and visualisation artifacts.

Sites. Leighton Moss RSPB Nature Reserve and Bonn Botanische Gärten are very different environments—one in a relatively remote rural area, the other in the centre of a city. The reasons for their selection are multiple. The former is a relatively dark site that offers a datum for much brighter urban sites. Both are well supported by staff who are familiar with the sites. Each site has electrical power and Internet, which are required for all-sky astronomical cameras. Both sites are well suited to the use of Internet-of-Things (IoT) infrastructure—Bonn had existing public IoT coverage, while LMRSPB has an open landscape that can be covered by the installation of a single IoT gateway. Both sites have experts and site managers who are interested in methods that can engage visitors with their environments in novel and creative ways.

IoT Infrastructure. LoRaWAN was chosen for the IoT infrastructure for the two projects. LoRaWAN is a robust IoT protocol that is increasingly being deployed to underpin municipal smart city systems, smart homes, and agriculture across the globe—examples include city-wide coverage in the cities of Hangzhou and Ningbo in Zhejiang province, China [22]. LoRaWAN is a protocol for long-range low-power wide area network communication infrastructure. It is an open standard and operates on unlicensed bands—868 KHz in the United Kingdom and Europe and 915 KHz in China—which are capable of seven to ten kilometers coverage in open landscapes and up to two kilometers in an urban setting. The LoRaWAN protocol meets international regulations for wireless communication and is thus suitable for global deployments.

The projects used publicly available LoRaWAN network infrastructure provided by The Things Network (TTN), which operates internationally. TTN has a strong community and ecosystem that offers resources to support developers and users. In Bonn, TTN network infrastructure is well established and publicly available [23] with good coverage of the city (Figure 1a). Meanwhile, in Leighton Moss, it was necessary to install a LoRaWAN gateway, which now contributes to the TTN infrastructure, extending TTN’s public network coverage to the Leighton Moss area (Figure 1b).

Figure 1. a) The Things Network IoT coverage in Bonn, Germany (https://www.thethingsnetwork.org/community/bonn/) and (b) Leighton Moss RSPB Nature Reserve, Northwest England. Software radio mapping to determine expected IoT coverage when installing one gateway (Google Earth, 2023; CloudRF, 2023).

Sensors and housings. Unattended sensors were designed to collect a range of parameters related to rhythms of environmental light and darkness. Very low power microcontroller boards were developed and connected to various sensor components, including lux sensors capable of detecting small variations in light at night, such as moonlight; RGB sensors that can capture variations in the colour of skyglow at night; ultraviolet sensors that can capture changes in the intensity of sunlight during the day; 10-channel spectrometers that capture the phenological rhythms of flora; and temperature, humidity, and air pressure sensors. The microcontrollers were programmed to capture readings every three minutes. Housings were designed to protect the sensors and batteries from the weather, while creating sculptural objects that are aesthetically sympathetic to their environment and engaging for people. Sculptural artifacts were developed, designed to resemble fruits and eggs (Figure 2).

Figure 2. Light sensor encased in resin; 3D-printed light-sensors hung in trees in the Bonn Botanische Gärten, Germany (author, 2022, 2023).

Data and database. Observations collected and transmitted by the sensors. These are picked up by LoRaWAN gateways registered to TTN, which broadcasts these to the Internet. A database server listens for and receives these broadcasts as they come, recording them in a time-series database (InfluxDB). Data from the database is sent to a WordPress webserver, where a JavaScript code interprets and visualizes the data.

Representing Data. These projects focus on the urban night to create a new awareness of the complexity of night-time environments, capturing the nuance and rhythms of anthropogenic skyglow, local glare from buildings, lighting, and traffic, lunar cycles, air traffic, the presence or absence of stars, (and occasional meteors and the milky way on a very clear night in rural areas). This data is interpreted through timepieces with diurnal, circalunar, and annual scales, revealing the centrality of cycles of light and dark in both urban and rural landscapes, while revealing the extent of anthropogenic light in urban environments. Figure 3 shows examples of this—here, each rotation represents a single day with the outer spiral terminating in the present moment. The moon phases can be clearly seen in Leighton Moss on the left, while the bright sky glow of Bonn’s urban night is clearly visible on the right, and both show the lengthening day through the Winter solstice as we move towards the spring equinox. This provides a powerful tool for communicating the entwinement of daily life with urban processes and wider planetary and cosmological scales [21][24].

An all-sky astronomical camera (Starlight Xpress Oculus 180) was also installed at each site, each connected to a miniPC. Software (AllSkeye) controls the camera and the data it collects. The camera takes a long exposure photograph every 30 seconds from 30 mins before sunset until 30 mins after sunrise (Figure 4). The software creates a stop-frame animation from the previous night’s captures and uploads the movie and photos to server, where it is stored, along with the photographs, and sent on to a WordPress website [24].

Figure 3. Time piece showing changing patterns of light and dark over a period of two months from December to January 2023/24 in Leighton Moss RSPB Nature Reserve (left) and Bonn Botanische Gärten (right) (author, 2024).

Figure 4. All-sky astronomical camera showing night sky in Leighton Moss RSPB Nature Reserve, United Kingdom (left) and Bonn Botanische Gärten (right) (author, 2024).

Participatory Workshops

In March 2024, the researcher and two colleagues ran workshops at Leighton Moss RSPB Nature Reserve to determine how the work at both sites can be used to engage citizens and understand how darkness and artificial light at night are perceived and understood. Participants included local people, international visitors, retirees, university staff, and local councillors. The workshops included a talk by astronomer Hannah Dalgleish, who discussed examples of light pollution, such as the Luxor Hotel in Las Vegas, which installed a pillar of light so bright that it has created its own ecosystem of bats, moths, owls, and locusts. This was followed by a talk by the author about the sensors installed in Leighton Moss and Bonn Botanische Gärten and the data visualizations, explaining how the visualizations captured the changes in light during the day and night over various timescales and how this varied considerably between urban and rural areas, particularly with respect to skyglow and the visibility of stars and the lunar phases. It also demonstrated how the all-sky camera is able to capture anthropogenic activity, such as the glare from housing, car headlights, and passing trains, as well as localized patches of skyglow on the horizon. This was followed by a haptic workshop led by Kath McDonald, where participants were invited to model clay with their eyes closed, exploring the experience of darkness through the body and imagination. Finally, as dusk fell, we undertook a night walk without torches, which continued into darkness.

Participants were asked to fill out questionnaires after the workshop. Results included: for 44% of respondents, this was their first night walk without a torch; 56% thought light pollution to be a more serious issue than they had previously; 89% would consider using lighting differently in their home and garden as a result of the event; and 56% felt more comfortable in the dark as a result of the event. Of the respondents, all stated that they would go on another night walk without a torch in the future. Participants also enquired about practical steps they might take to address light pollution, asking for ‘information about local groups that are trying to promote dark skies’, ‘more examples of what we could do to change things’, and ‘how [the author’s] is working with different sites to apply his research and what changes this has resulted in at those sites’.

Coda

Although smart cities engage with complex intertwined spatiotemporal patterns of change, those patterns are dampened, inflected, and subordinated to fit into desired patterns of efficiency [12], often hiding the underlying planetary processes that drive behaviour. The work discussed in this paper demonstrates how smart city infrastructures can be used to engage citizens in environmental discourse and stewardship. It provides material for urban and rural imaginaries that help situate the individual within spatiotemporal scales that include and extend those of daily life to the planetary and cosmological scales that choreograph life, ecologies, and earth processes. These resultant imaginaries move beyond traditional smart city and urban ecological imaginaries that render the city as fluid, frictionless, relatively self-contained, and distanced from a planetary view of nature. Such expanded cosmocentric imaginaries are urgently needed to support the radical societal changes that are required to limit global warming, environmental degradation, and biodiversity loss within which cities across the globe are inextricably entwined.

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