Cotonou Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

18.94

Bortle class

Class 7 (Class 7)

Darkness Quotient

32%

Dataset

April 2026

Suburban/urban transition

Cotonou: The Practical Verdict

Cotonou, as a major city in Benin, offers a sky heavily influenced by urban lighting, with limited visibility for astronomical observations. Overall, it falls within the category of high light pollution, making deep-sky observing and Milky Way visibility nearly out of reach. The brightest horizons further detract from the stargazing experience here.

From this location, effective observing is confined to the Moon, planets, and a few bright stars, while deep-sky objects require the help of narrowband filters or imaging techniques. Targets like faint nebulae or galaxies remain inaccessible, and the Milky Way is rendered invisible under such conditions.

For a substantially darker sky, consider travelling west to Dovikondji in Mono Department, about 70 km away. There, the sky is significantly clearer, providing better conditions for deep-sky astronomy including nebulae and distant galaxies.

At a Glance

Overall

Poor urban/suburban sky - This is a poor sky for astronomy. The Moon, planets, and a few bright objects remain viable, but deep-sky work is difficult.

Milky Way

Not visible - The Milky Way is not realistically visible from this level of light pollution.

Best targets from here

Moon, planets, bright double stars, bright open clusters, narrowband imaging with careful processing

Do not prioritise

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

Best nearby upgrade

Dovikondji, Mono Department sits about 70 km west and reaches Bortle 3, roughly 9.5x darker.

Good dark window

Cotonou retains astronomical darkness throughout the year, so seasonality is less extreme than at higher latitudes. The main limitation is light pollution, not the length of the dark window.

Frequently Asked Questions

Can you see the Milky Way from Cotonou?

No. Cotonou is a Bortle Class 7 sky with SQM 18.94, 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 Cotonou?

Cotonou is Bortle Class 7 (SQM 18.94), a poor urban/suburban sky for astronomy.

Is Cotonou good for stargazing?

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

Is Cotonou good for astrophotography?

Broadband deep-sky imaging is heavily compromised from Cotonou and a Bortle 4 or darker site is strongly recommended. Narrowband imaging of bright emission nebulae remains viable from Cotonou with appropriate Ha or OIII filters.

What can you observe from Cotonou?

Primary targets from Cotonou include Moon, planets, bright double stars, bright open clusters, narrowband imaging with careful processing. Targets such as visual deep-sky observing, broadband galaxies, reflection nebulae are not realistic from this sky.

Where are darker skies near Cotonou?

The closest meaningfully darker mapped site is Agonkèssa, Atlantique Department, about 24 km north north west of Cotonou, reaching Bortle 6.

When is the sky darkest in Cotonou?

The sky over Cotonou is darkest around January, November.

Is light pollution in Cotonou getting better or worse?

The long-term trend for Cotonou is gradually worsening, with the sky brightening by about 0.04 SQM per year.

• Agonkèssa, Atlantique Department

  Direction

  NNW

  Distance (km)

  24.1

  SQM

  20.23

  Bortle

  6

• Dovikondji, Mono Department

  Direction

  W

  Distance (km)

  70

  SQM

  21.38

  Bortle

  3

• Kweme, Lagos State

  Direction

  E

  Distance (km)

  35.7

  SQM

  20.08

  Bortle

  6

• Djègbadji, Atlantique Department

  Direction

  W

  Distance (km)

  36.3

  SQM

  20.09

  Bortle

  6

• Gadéhoué, Kouffo Department

  Direction

  WNW

  Distance (km)

  83.3

  SQM

  20.12

  Bortle

  6