A remarkable sky.
A shared responsibility.

Two boundaries, with different purposes

The work was undertaken at two levels. An overall Reserve boundary encompasses the wider landscape proposed for designation. Within it, a more selectively defined Core Zone focuses on the darkest and least developed areas, separating them from roads, buildings and likely artificial-light sources as far as practicable.

Defining the overall Reserve

The proposed area extends from Loch Carron at its southern limit to the north coast around Melvich Bay and Halladale. The western and northern sides make extensive use of the natural coastline, with appropriate offshore islands included where they form part of the wider dark landscape.

The inland boundary was digitised with reference to recognisable landscape features. Rivers and watercourses, catchments, watersheds, ridges and topography were considered alongside settlement patterns, existing land designations and other identifiable features. This produces a geographical boundary rather than one based solely on a fixed radius or administrative unit.

The assessment used Ordnance Survey mapping and terrain information, roads, buildings, settlements, surface water, contours, woodland and place names. Environmental reference layers included Sites of Special Scientific Interest, Special Areas of Conservation, Special Protection Areas, Ramsar sites, National Nature Reserves, Wild Land Areas and National Scenic Areas.

The relationship with The Flow Country World Heritage Site, Wester Ross Biosphere and North West Highlands Geopark, all UNESCO sites, was also considered.

Identifying the Core Zone

The core was developed separately and assessed against more restrictive criteria. Its purpose is to focus protection on extensive areas of natural darkness, paying particular attention to roads, buildings, settlements and associated artificial-light sources.

A GIS setback approach separates the principal core from developed and regularly trafficked areas. An approximately one-kilometre setback from roads and developed corridors provides separation from places where permanent or intermittent lighting is most likely to occur.

Many road corridors and concentrations of buildings therefore remain in the wider Reserve rather than becoming part of the main core, even where the surrounding landscape is very dark. These areas still have a role in responsible lighting and protection of the night-time environment.

This distinction matters in the Highlands, where roads and inhabited glens penetrate remote country. Including every road corridor would overstate the Core’s separation from light sources; dividing it wherever a road occurs would fragment an otherwise extensive dark landscape.

Connecting the dark landscape

A limited number of connecting core corridors were incorporated to maintain continuity between major areas of dark landscape. Their alignments were examined against roads, buildings, terrain and other mapped features, and selected to minimise exposure to development and artificial lighting.

Corridor centre-lines were defined in the GIS and buffered by 500 metres on each side, giving a corridor approximately one kilometre wide. This corridor width is distinct from the approximately one-kilometre setback used around roads in the principal core.

Where possible, the corridors run through undeveloped terrain and away from buildings. Some cross or incorporate short sections of road to connect substantial dark areas. Their inclusion recognises the continuity of the surrounding landscape; it does not imply that the road itself is free of light or traffic.

The connections were reviewed iteratively. Less suitable alignments could be removed and alternatives assessed, so that the proposed Core reflects landscape conditions as well as the GIS analysis.

Buildings and transport routes

Mapped buildings were checked within and near the Core because they may represent existing light sources or locations where future lighting could affect sky quality. Individual structures need to be assessed rather than assuming that apparently remote land is entirely undeveloped.

National, regional and local roads were considered separately, allowing major transport routes to be distinguished from minor roads and tracks.

The core is intended to be overwhelmingly characterised by remote, undeveloped dark landscape. It is not a claim that no roads, buildings or artificial lights occur anywhere within it. Buildings should be considered according to their use, access and lighting characteristics.

67 mapped buildings within the proposed Core

The project’s GIS assessment identifies 67 buildings within the proposed Core Zone. These remote shelters are characteristic of the Highland landscape and should be distinguished from permanently occupied houses, commercial premises and other buildings likely to produce regular artificial light.

Bothies are generally simple shelters reached on foot, commonly without conventional road access, mains electricity or permanent external lighting. Some may be reached by estate or ATV tracks. Their presence does not have the same lighting implications as an inhabited settlement or illuminated roadside property; individual access and lighting arrangements still need to be checked.

Bothies also provide established destinations and shelter in remote country, allowing people to spend time within dark landscapes without requiring new permanent accommodation or lighting infrastructure.

Paths and practical access into the Core

The main recognised paths and long-distance trails within the Reserve have been mapped as part of the assessment. They demonstrate an existing network through which walkers can reach well into the Core, without needing additional roads or major access infrastructure.

In many locations, the approximately one-kilometre road setback places the Core within roughly a 15-minute walk of suitable access points, including recognised walkers’ car parks, for reasonably mobile visitors on suitable terrain. Actual time varies with the route, gradient, surface, weather and darkness; this is not a guarantee for every location or visitor.

The design balances separation from development with the ability to experience the dark landscape without always undertaking a major expedition. The mapped paths can also help identify places for future guided walks, interpretation and observing opportunities.

Access for people with limited mobility

Carefully selected road-accessible core connections have an additional benefit. They may allow people who cannot negotiate remote mountain paths, particularly after dark, to experience the Core landscape and its night sky.

These connections were chosen as far from settlements, concentrations of buildings and other development as practicable. The aim is to retain selected opportunities for access without a substantial walk over difficult terrain, while preserving the predominantly remote character of the Core.

A road-accessible area is not automatically a wheelchair-accessible observing site. Nearby buildings, lighting, traffic, stopping places, parking and surface conditions need individual assessment before particular locations are recommended for accessible observation.

The maps are not navigation guides. Specific routes, observing places and access arrangements require local confirmation, clear guidance and consideration of homes, working land, safety and sensitive habitats.

Wind turbines and the proposed Core Zone

Wind turbine locations and development status were included in the GIS assessment used to refine the proposed Core Zone. A one-kilometre buffer was applied around all turbines recorded as constructed or under construction, and these buffered areas were excluded from the Core.

The project’s current GIS assessment identifies 200 constructed or under-construction turbines within the wider proposed Reserve, with none within the revised Core Zone. This distinction reflects the intention to focus the Core on predominantly undeveloped dark landscapes while recognising existing infrastructure within the wider Reserve. The one-kilometre buffer is a boundary-selection measure; it does not imply that lighting effects necessarily stop at that distance.

The assessment also identifies a further 451 turbine records at various stages of approval, planning or preliminary assessment within the Reserve, some of which fall within the proposed Core. These proposals are considered separately from existing and under-construction turbines, because their planning status, layouts and eventual delivery may change.

Where aviation warning lighting is required, we would encourage developers and the relevant authorities to consider Aircraft Detection Lighting Systems (ADLS), where technically suitable and consistent with applicable aviation requirements. These systems allow warning lights to remain off when aircraft are absent from the relevant detection area, activating them when needed for aviation safety. Required testing and fail-safe operation can also cause the lights to illuminate.

The aim is to support constructive discussion about renewable energy, aviation safety and protection of the natural night-time environment. Proposed developments within or near the Core will require individual assessment, including their potential lighting effects and any implications for the proposed boundary.

Turbine counts: project GIS assessment, October 2026. Aviation lighting guidance: CAA CAP 764: Policy and Guidelines on Wind Turbines.

Core Zone: verified development and lighting inventory

The revised Core Zone measures 4,129.4 km². GIS mapping identifies 67 buildings within it, none with a direct road connection. Their remote locations suggest many may be bothies or shelters, but building uses and residential status have not yet been individually verified.

An intersection of the revised Core boundary with Highland Council’s supplied street-lighting inventory returned zero recorded Council street-lighting assets. This is not a complete inventory of privately operated, agricultural, commercial or other lighting and does not establish that every part of the Core is free of artificial light.

The Core contains no constructed or under-construction wind turbines in the project’s mapped turbine dataset. Future turbine proposals would be considered under applicable planning and aviation safety requirements. The proposed Lighting Management Plan would seek to avoid unnecessary permanent obstruction lighting and, where aviation lighting is required, favour approved aircraft detection lighting systems (ADLS) or equivalent controls where feasible and authorised. ADLS is a proposed policy direction, not a current statutory requirement.

Existing landscape designations and planning controls

The latest GIS intersections show that 4,126.97 km² (99.94%) of the Core overlaps one or more of eight mapped environmental and landscape designation categories. Within this, 2,760.05 km² (66.84%) overlaps the six statutory and associated conservation designation categories considered in the project; 1,682.63 km² (40.75%) lies within four National Scenic Areas. These figures overlap and must not be added together. The eight-category total includes non-statutory designations and does not mean that 99.94% has legal protection specifically for darkness.

National Scenic Areas and conservation sites already benefit from statutory planning or conservation controls, but these are not equivalent to a universally applicable Article 4 Direction, nor do they automatically make a dark-sky Lighting Management Plan enforceable. The project will explore with Highland Council how an adopted lighting policy, relevant planning controls and agreements with lighting and land-management authorities could provide consistent, enforceable management across the proposed Reserve. Existing light sources, private installations and development not subject to planning consent may need separate measures.

The Core’s limited mapped development makes a preventative Lighting Management Plan a realistic objective: maintaining existing darkness and addressing future proposals, rather than undertaking extensive retrofitting of Council streetlights within the Core. Public outreach would be focused on suitable accessible observing locations, avoiding unnecessary pressure on sensitive habitats.

Checking the proposal against night-time light data

The boundaries were considered alongside independent night-time light datasets. VIIRS annual radiance data show the distribution of upward light detected by satellite. The World Atlas of Artificial Night Sky Brightness, published by Falchi and colleagues in 2016 and labelled World Atlas 2015 on the supplied map, models artificial zenith sky brightness at ground level.

These datasets complement each other. VIIRS records light detected from above; the World Atlas estimates its contribution to the sky seen from the ground. Together with settlement, building and transport mapping, they help assess whether the proposed Core corresponds to the darkest parts of the Reserve.

The overall design principle

The approach seeks to achieve four connected objectives:

• Protect the darkest landscapes.
• Minimise exposure to settlements, buildings and significant transport-related lighting.
• Maintain practical pedestrian access through established paths.
• Provide selected opportunities for people with limited mobility to experience the Core.

The wider Reserve contains communities, roads and inhabited landscapes; the Core focuses more selectively on remote dark areas, with existing paths, bothies and carefully considered connections. Its purpose is a dark landscape that can be protected, experienced and enjoyed.

The current proposed areas remain 7,537.7 km² overall, including 4,129.4 km² of core (54.78%) and 3,408.3 km² of periphery (45.22%). The boundaries are an evidence-led proposal, capable of refinement through field assessment, consultation, lighting inventories and direct sky-quality measurements.