Cardiff Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

18.54

Bortle class

Class 8 (Class 8)

Darkness Quotient

28%

Dataset

April 2026

City sky

Cardiff: The Practical Verdict

Cardiff, a mid-size city in Wales, experiences high levels of light pollution that result in its sky being categorised as Bortle 8. Stargazing from within the city is quite limited, with the urban brightness effectively erasing most celestial detail.

The Milky Way is completely invisible here, and deep-sky observing for faint galaxies and nebulae is impractical. However, brighter targets like the Moon, planets, and the occasional bright open cluster remain accessible, particularly for visual observing or narrowband imaging setups.

For those seeking better skies, venturing south-west towards regions such as Inwardleigh offers a considerable upgrade, with Bortle 3 conditions and a markedly darker sky backdrop. This is worth exploring for serious deep-sky observation.

At a Glance

Overall

Poor city sky - This is a poor city sky. The Milky Way is not visible and most deep-sky observing is unrealistic from the location itself.

Milky Way

Not visible - The Milky Way is erased by the bright urban sky background.

Best targets from here

Moon, planets, bright stars, double stars, solar system events, narrowband imaging only with care

Do not prioritise

visual deep-sky observing, broadband galaxies, reflection nebulae, widefield Milky Way

Best nearby upgrade

Inwardleigh sits about 100 km south west and reaches Bortle 3, roughly 16x darker.

Moderate dark window

Cardiff's longest dark windows fall in December and January, with the shortest nights around June and July. Plan deep-sky sessions around the autumn and winter months for the best combination of long nights and true astronomical darkness.

Frequently Asked Questions

Can you see the Milky Way from Cardiff?

No. Cardiff is a Bortle Class 8 sky with SQM 18.54, so the Milky Way is not visible from the city. For Milky Way photography, look for a Bortle 4 or darker site.

What Bortle class is Cardiff?

Cardiff is Bortle Class 8 (SQM 18.54), a poor city sky for astronomy.

Is Cardiff good for stargazing?

Not for serious deep-sky observing. Cardiff is a poor city sky where the Moon, planets, and a handful of bright targets are the realistic options from the city itself.

Is Cardiff good for astrophotography?

Broadband deep-sky imaging is heavily compromised from Cardiff and a Bortle 4 or darker site is strongly recommended. Even narrowband imaging is difficult from Cardiff without careful processing.

What can you observe from Cardiff?

Primary targets from Cardiff include Moon, planets, bright stars, double stars, solar system events. Targets such as visual deep-sky observing, broadband galaxies, reflection nebulae are not realistic from this sky.

Where are darker skies near Cardiff?

The closest meaningfully darker mapped site is The Herberts, about 18 km west south west of Cardiff, reaching Bortle 5.

When is the sky darkest in Cardiff?

The sky over Cardiff is darkest around January, December. Significant summer limitation: around 59 nights per year have no true astronomical darkness.

Is light pollution in Cardiff getting better or worse?

Long-term light pollution over Cardiff has been broadly stable across the available measurements.

• The Herberts

  Direction

  WSW

  Distance (km)

  17.5

  SQM

  20.33

  Bortle

  5

• Lincombe

  Direction

  WSW

  Distance (km)

  72.5

  SQM

  21.47

  Bortle

  3

• Hemyock

  Direction

  S

  Distance (km)

  64.3

  SQM

  21.00

  Bortle

  4

• Llangadog

  Direction

  NW

  Distance (km)

  64.1

  SQM

  20.78

  Bortle

  5

• Silverlake

  Direction

  SSE

  Distance (km)

  73.4

  SQM

  21.05

  Bortle

  4

• Inwardleigh

  Direction

  SW

  Distance (km)

  100.2

  SQM

  21.54

  Bortle

  3