Cardiff Stargazing & Astronomy Report
Light pollution and stargazing locations near Cardiff
- City
- Cardiff
- Country
- United Kingdom
- Latitude
- 51.4816
- Longitude
- -3.1791
Key Sky Quality Metrics
- SQM (mag/arcsec²)
- 18.14
- Bortle class
- Class 8 (Class 8)
- Darkness Quotient
- 24%
- Dataset
- March 2026
City sky
Cardiff stargazing at a glance
Cardiff is the capital of Wales, a lively waterfront city on the south coast with a compact urban core and a broad metropolitan glow stretching across the surrounding area.
The city generally experiences High Light Pollution, with a Darkness Quotient of 24% — placing it among the more light-polluted cities in the UK, though not at the very brightest extreme of the largest global metros. For practical observing from within the city, the most reliable targets are the Moon, planets, double stars and the brightest open clusters. Fainter deep-sky objects are heavily washed out by the urban skyglow.
Meaningfully darker skies are not close at hand, and a proper improvement usually means leaving the city well behind. The nearest reasonable darker option is about 90 kilometres to the east-south-east near Near Wiltshire, England, while very dark skies are available at roughly 95 kilometres to the south-west near Near West Devon, England.
The map shows Cardiff as part of a broad bright belt along the south coast, with intense pink-white urban cores embedded in wider red, orange and yellow skyglow. That pattern points to a strong city light dome rather than a sharply isolated patch of brightness, so the glow spills well beyond the built-up area.
The darkest tones on the map appear most clearly offshore to the west and north-west, where the colours quickly fall away through blue into grey and near-black. Over land, darker regions are more fragmented, with noticeably better conditions developing away from the main urban belt to the west, south-west and parts of the north and north-west.
Compared with its surroundings, Cardiff sits in a distinctly brighter zone than the rural land beyond it, and the eastward side of the map remains especially busy with additional clusters of light. In practical terms, that means the city is much brighter than the countryside around it, but the cleanest break from the glow comes only after a fairly substantial journey.
What the sky is like overhead
Looking straight up from Cardiff, the zenith is still heavily affected by city lighting. With an SQM reading of 18.14, the overhead sky is bright enough that familiar constellations remain visible, but the background never becomes properly dark.
In practice, the Moon and planets stand out well, and the brighter stars of the main seasonal patterns are easy enough to pick out once you know where to look. The Milky Way is effectively lost from the city, and many fainter stars that would normally fill in the constellations are missing.
This gives Cardiff a typical bright-city sky: recognisable star patterns overhead, but limited contrast and little sense of a richly populated background sky.
north - fair
About 15 kilometres north of Cardiff, conditions are fair, with a Bortle 5 sky that is noticeably better than the city centre but still not truly dark. In this direction, genuinely dark skies become reachable at around 50 kilometres.
north-north-east - marginal
About 15 kilometres north-north-east of the city, the sky is marginal, corresponding to Bortle 6 conditions. It improves further with distance, and genuinely dark skies are reached at around 50 kilometres in this direction.
north-east - poor
At roughly 15 kilometres to the north-east, the sky is still poor, with Bortle 7 conditions and plenty of lingering urban glow. It does improve to useful darker country sky farther out, but genuinely dark skies are not reached within the sampled distance in this direction.
east-north-east - marginal
Around 15 kilometres east-north-east of Cardiff, conditions are marginal under a Bortle 6 sky. A more substantial improvement arrives farther out, with genuinely dark skies appearing at around 100 kilometres.
east - fair
About 15 kilometres east of the city, the sky is fair at Bortle 5, so brighter targets become easier but the background remains obviously lit. Genuinely dark skies are not reached within the sampled distance in this direction.
east-south-east - fair
At around 15 kilometres east-south-east, the sky is fair with Bortle 5 conditions. There is a worthwhile improvement farther out towards darker rural sky, but genuinely dark skies are not reached within the sampled distance in this direction.
south-east - fair
About 15 kilometres to the south-east, conditions are fair, with a Bortle 5 sky and clear remaining light pollution. This direction does improve steadily, but genuinely dark skies only appear much farther out at around 200 kilometres.
south-south-east - fair
At roughly 15 kilometres south-south-east of Cardiff, the sky is fair under Bortle 5 conditions. A much darker step up is available farther out, with genuinely dark skies reached at around 100 kilometres.
south - fair
Around 15 kilometres south of the city, the sky is fair and still affected by the urban light dome, corresponding to Bortle 5. In this direction, genuinely dark skies become available at around 100 kilometres.
south-south-west - fair
About 15 kilometres south-south-west, conditions are fair with a Bortle 5 sky. The improvement becomes much more pronounced farther out, and genuinely dark skies are reached at around 50 kilometres.
south-west - marginal
At roughly 15 kilometres south-west of Cardiff, the sky is marginal at Bortle 6, so urban glow still has a strong presence. The good news is that this direction improves well, with genuinely dark skies available at around 50 kilometres.
west-south-west - fair
Around 15 kilometres west-south-west of the city, the sky is fair, with Bortle 5 conditions. A stronger jump to genuinely dark sky arrives at around 50 kilometres in this direction.
west - fair
About 15 kilometres west of Cardiff, conditions are fair under a Bortle 5 sky. The direction continues to improve, with genuinely dark skies reached at around 100 kilometres.
west-north-west - marginal
At roughly 15 kilometres west-north-west, the sky is marginal, corresponding to Bortle 6 conditions. It remains uneven for a while, but genuinely dark skies do appear farther out at around 100 kilometres.
north-west - marginal
Around 15 kilometres north-west of the city, conditions are marginal with a Bortle 6 sky. A clearer break into genuinely dark conditions comes at around 50 kilometres in this direction.
north-north-west - fair
About 15 kilometres north-north-west of Cardiff, the sky is fair at Bortle 5, with a noticeable but incomplete escape from city glow. This direction improves strongly farther out, reaching genuinely dark skies at around 50 kilometres.
zenith - poor
Looking straight up from Cardiff, the zenith is poor, with a Bortle 8 sky and a bright urban background. The main constellations are still visible, but many fainter stars are missing, and the Milky Way is effectively invisible from within the city.
-
Near Powys, Wales
- Direction
- WNW
- Distance (km)
- 111.5
- SQM
- 21.55
- Bortle
- 3
Milky Way visible, broadband DSO imaging
-
Near West Devon, England
- Direction
- SW
- Distance (km)
- 95.2
- SQM
- 21.50
- Bortle
- 3
Milky Way visible, broadband DSO imaging
-
Near Wiltshire, England
- Direction
- ESE
- Distance (km)
- 87.6
- SQM
- 21.02
- Bortle
- 4
Bright nebulae, galaxies, narrowband imaging
Genuinely dark skies require a meaningful drive from Cardiff rather than a quick hop out of town.
The nearest Bortle 4 conditions are about 90 kilometres to the east-south-east near Near Wiltshire, England, while the nearest very dark site in the supplied locations is around 95 kilometres to the south-west near Near West Devon, England. Closer to the city, the sky does improve in several directions, but it generally stays noticeably affected by urban glow.
-
Within 100 km
- Place
- Near West Devon, England
- Direction
- SW
- Distance (km)
- 95.2
- SQM
- 21.50
- Bortle
- 3
-
Within 200 km
- Place
- Near Powys, Wales
- Direction
- WNW
- Distance (km)
- 111.5
- SQM
- 21.55
- Bortle
- 3
Long-term trend
Cardiff's long-term trend is slightly encouraging. The measured sky brightness has improved from 17.81 in the earliest record to 18.14 in the latest one, with an average annual change of about +0.03 SQM across 75 datasets.
That is a modest shift rather than a dramatic one, and the city still sits firmly in a bright-sky regime for astronomy. Even so, the overall direction is towards a slightly darker zenith than in the earliest measurements.
The full historical range runs from 17.81 at the brightest end to 18.81 at the darkest, which suggests some variation over time but no major transformation in observing conditions from within the city itself.
From within Cardiff, the strongest targets are the obvious bright ones: the Moon, the planets, double stars and a handful of bright open clusters. These cope best with the bright background sky and still give rewarding views.
A few brighter deep-sky objects can be attempted with patience, especially showpiece objects such as M42 or the brightest globular clusters, but contrast is the main problem rather than magnification. They are much easier from outside the city.
For the Milky Way, faint galaxies, diffuse nebulae and meteor watching, a darker site makes a huge difference. Those are the targets that really benefit from getting well clear of Cardiff's light dome.
- Moon
- planets
- double stars
- brightest open clusters
- bright nebulae such as M42
- the brightest globular clusters
- Milky Way
- faint galaxies
- broadband nebulae
- meteor showers
Can you see stars from Cardiff?
Yes — you can still see plenty of the brighter stars and the main constellations from Cardiff. What you lose is the fainter background star field that makes the sky look rich and densely populated from darker places.
Can you see the Milky Way from Cardiff?
For most observers within the city, no. Cardiff's sky is bright enough that the Milky Way is effectively washed out.
What Bortle class is Cardiff?
Cardiff is Bortle Class 8, which is a bright city sky. That means astronomy from within the city is mainly focused on the Moon, planets and other brighter objects.
What is the SQM in Cardiff?
The latest supplied zenith reading for Cardiff is 18.14 SQM. That is firmly in bright urban territory rather than genuinely dark sky.
Where are the nearest dark skies from Cardiff?
The nearest reasonable darker site in the supplied locations is Near Wiltshire, England, about 87.6 kilometres to the east-south-east, where conditions reach Bortle 4. For darker still conditions, Near West Devon, England lies about 95.2 kilometres to the south-west and reaches Bortle 3.
Is Cardiff good for astrophotography?
It can be decent for lunar, planetary and narrow-field astrophotography, especially for bright subjects. For wide-field nightscapes, the Milky Way or faint deep-sky imaging, you will get much better results by travelling to darker skies.
How far do you need to drive from Cardiff for darker skies?
For a clear improvement, you are generally looking at something like 90 kilometres to reach Bortle 4 conditions near Near Wiltshire, England. Very dark skies are available at a similar sort of distance, with Near West Devon, England around 95 kilometres away and Near Powys, Wales about 111.5 kilometres away.