Cotonou Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

19.03

Bortle class

Class 7 (Class 7)

Darkness Quotient

33%

Dataset

August 2026

Suburban/urban transition

Cotonou: The Practical Verdict

Cotonou, a major city in Benin, is heavily impacted by light pollution, classifying its night sky in the category of poor urban/suburban conditions. With a Bortle class of 7, few celestial objects make it through the light dome, meaning the Milky Way remains elusive. The overwhelming urban glow significantly restricts visibility, with artificial lighting as the primary challenge.

While the Milky Way is not visible from Cotonou, the Moon, planets, and bright double stars remain accessible for observation. For astrophotographers, narrowband imaging of bright emission nebulae is possible with care and processing. More traditional visual deep-sky observing, however, is largely unfeasible due to the pervasive urban light.

If you're seeking somewhat darker conditions, a site around 30 km north-north-west of Cotonou offers modest improvement. However, this region is still subject to similar urban pollution challenges and won't provide the pristine views some might hope for.

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

Limited nearby upgrade

30 km NNW is the strongest nearby option but remains Bortle 6; the improvement is real but modest.

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 19.03, 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 19.03), 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 30 km NNW, about 30 km north north west of Cotonou, reaching Bortle 6.

When is the sky darkest in Cotonou?

The sky over Cotonou is darkest around January, December.

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.

• 30 km NNW

  Direction

  NNW

  Distance (km)

  30.2

  SQM

  20.27

  Bortle

  6

• 5 km ESE

  Direction

  ESE

  Distance (km)

  5

  SQM

  19.71

  Bortle

  6

• 45 km E

  Direction

  E

  Distance (km)

  44.8

  SQM

  20.25

  Bortle

  6

• 14 km W

  Direction

  W

  Distance (km)

  13.6

  SQM

  19.67

  Bortle

  6