Ottawa Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

17.56

Bortle class

Class 9 (Class 9)

Darkness Quotient

19%

Dataset

April 2026

Inner city sky

Ottawa: The Practical Verdict

Ottawa, a major city in Ontario, offers severely compromised stargazing conditions due to its extreme urban light pollution. The sky is rated as Bortle 9, making deep-sky observing and Milky Way viewing completely unfeasible.

Only the brightest targets such as the Moon, planets, and double stars are reliably visible against the city's bright backdrop. Imaging should focus on narrowband techniques for limited success, while broadband photography will struggle with significant gradients. Deep-sky objects and widefield views are overwhelmed by light pollution.

For improved conditions, consider travelling about 115 km south to the Town of Gouverneur, New York, where darker skies rated as Bortle 4 offer a substantial reduction in light pollution and open up more possibilities for deep-sky observation and imaging.

At a Glance

Overall

Severe urban sky - This is a severely light-polluted urban sky. Only the Moon, planets, bright stars, and a few specialist targets remain practical.

Milky Way

Not visible - The Milky Way is not visible from this sky.

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

Town of Gouverneur, New York sits about 117 km south and reaches Bortle 4, roughly 28x darker.

Moderate dark window

Ottawa'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 Ottawa?

No. Ottawa is a Bortle Class 9 sky with SQM 17.56, 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 Ottawa?

Ottawa is Bortle Class 9 (SQM 17.56), a severe urban sky for astronomy.

Is Ottawa good for stargazing?

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

Is Ottawa good for astrophotography?

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

What can you observe from Ottawa?

Primary targets from Ottawa 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 Ottawa?

The closest meaningfully darker mapped site is Fassifern, Ontario, about 79 km east of Ottawa, reaching Bortle 5.

When is the sky darkest in Ottawa?

The sky over Ottawa is darkest around January, December.

Is light pollution in Ottawa getting better or worse?

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

• Fassifern, Ontario

  Direction

  E

  Distance (km)

  78.6

  SQM

  20.30

  Bortle

  5

• Town of Gouverneur, New York

  Direction

  S

  Distance (km)

  117.3

  SQM

  21.17

  Bortle

  4

• Harrington, Quebec

  Direction

  ENE

  Distance (km)

  91.4

  SQM

  20.25

  Bortle

  6

• Kaladar, Ontario

  Direction

  WSW

  Distance (km)

  139

  SQM

  20.43

  Bortle

  5

• Prince Edward County, Ontario

  Direction

  SSW

  Distance (km)

  178.6

  SQM

  20.91

  Bortle

  4

• 274 km SSW

  Direction

  SSW

  Distance (km)

  274.4

  SQM

  21.51

  Bortle

  3