Copenhagen Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

17.66

Bortle class

Class 9 (Class 9)

Darkness Quotient

20%

Dataset

March 2026

Inner city sky

Stargazing in Copenhagen

Copenhagen is Denmark’s capital, a compact but influential Scandinavian waterfront city on the eastern side of Zealand, known for its harbours, bridges and dense urban character.

The city generally experiences Extreme Light Pollution, with a Darkness Quotient of 20% — placing it among the more light-polluted capitals in northern Europe.

For practical observing from within the city, the most realistic targets are the Moon, bright planets, double stars and the brightest open clusters. Fainter deep-sky objects are heavily washed out by the urban skyglow, though a few showpiece objects can still be attempted with patience.

Meaningfully darker skies do exist, but not right on the edge of the city. The nearest reasonable improvement is about 65 kilometres away to the west near Holbæk Municipality, Region Zealand, while truly dark conditions are available roughly 70 kilometres to the south-south-west near Vordingborg Municipality, Region Zealand.

The map shows Copenhagen as an intense urban core, with bright pink and red patches concentrated across the city and its built-up surroundings, fading outward through yellow, green and blue. That pattern is typical of a major capital whose light dome spreads well beyond the central districts and across the surrounding coastal development.

Even so, the image also shows that the brightest glow is broken up by water and by gaps between settlements, which helps the light dome thin out in some directions more quickly than in a continuous inland conurbation. Darker regions appear most clearly away from the main built-up belt, especially towards the south, south-east and parts of the wider north, where the background turns grey to black.

Compared with its surroundings, Copenhagen is plainly the dominant source of artificial sky brightness in the crop. Smaller towns and settlements show up as isolated yellow and red knots around the broader region, but none rival the scale or intensity of the capital’s glow.

What the sky overhead is like

Looking straight up from Copenhagen, the zenith remains very bright by astronomical standards. With an overhead reading of 17.66 and a Bortle 9 sky, the city background stays luminous enough to suppress much of the finer star field even when the weather is clear.

In practical terms, familiar constellations are still visible, but they appear thinned out, with the fainter linking stars missing and the overall sky lacking contrast. The Moon and planets cut through well, but the Milky Way is effectively lost against the bright urban background.

This is the kind of sky where astronomy from within the city is best approached selectively: bright, high-contrast targets can still be enjoyable, but faint structure and subtle detail are much better saved for a trip outside Copenhagen.

• Near Vordingborg Municipality, Region Zealand

  Direction

  SSW

  Distance (km)

  69.2

  SQM

  21.40

  Bortle

  3

  Milky Way visible, broadband DSO imaging

• Near Holbæk Municipality, Region Zealand

  Direction

  W

  Distance (km)

  65.1

  SQM

  21.16

  Bortle

  4

  Bright nebulae, galaxies, narrowband imaging

• Near Sjöbo kommun, Sweden

  Direction

  E

  Distance (km)

  83.3

  SQM

  21.10

  Bortle

  4

  Bright nebulae, galaxies, narrowband imaging

Genuinely dark skies are reachable from Copenhagen, but they do require a purposeful drive rather than a quick hop out of the centre.

The nearest Bortle 4 site is about 65 kilometres to the west at Near Holbæk Municipality, Region Zealand, while the closest truly dark option is roughly 70 kilometres to the south-south-west at Near Vordingborg Municipality, Region Zealand. In the immediate surroundings of the city, the sky remains heavily affected by Copenhagen’s broad light dome.

• Within 100 km

  Place

  Near Vordingborg Municipality, Region Zealand

  Direction

  SSW

  Distance (km)

  69.2

  SQM

  21.40

  Bortle

  3

Long-term sky trend

Copenhagen’s long-term trend is slightly encouraging, though the change is modest rather than dramatic. Across 75 datasets, the trend slope is +0.0131 SQM per year, with readings improving from 17.99 in the earliest record to 18.07 in the latest one.

That points to a very slow darkening over time, but the city still sits firmly in a very bright urban regime. In practice, any improvement is too small to transform what most observers will see from within the city itself.

The wider record also shows that Copenhagen can vary noticeably from one measurement to another, with values ranging from 17.81 up to 22.00. That sort of spread reflects changing observing conditions as well as the contrast between the city centre and much darker ground farther out.

From within Copenhagen itself, the best targets are bright, compact objects that can punch through a luminous background sky. The Moon, planets, double stars and the brightest open clusters are the most dependable choices.

A few showpiece deep-sky objects can still be attempted, especially bright nebulae such as M42 and the brightest globular clusters, but contrast is the limiting factor. They are usually better as telescopic challenges than easy visual targets.

For the Milky Way, faint galaxies, large diffuse nebulae and meteor watching, a darker site outside the city makes a huge difference. Those are the kinds of targets that benefit most from leaving Copenhagen’s urban glow behind.

• Moon
• planets
• double stars
• brightest open clusters

• bright nebulae such as M42
• the brightest globular clusters

• Milky Way
• faint galaxies
• broadband nebulae
• meteor showers