Philadelphia Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

16.98

Bortle class

Class 9 (Class 9)

Darkness Quotient

16%

Dataset

July 2026

Inner city sky

Philadelphia: The Practical Verdict

Philadelphia, a major city in the United States, unfortunately offers a severe urban sky for stargazing. The sheer scale of extreme light pollution means that this is one of the most challenging places for astronomy, with the Milky Way not visible at all.

Under these conditions, only the brightest objects remain accessible. The Moon, planets, and bright stars are reasonably visible, and double stars can be of interest. For those keen on imaging, narrowband filters may help, but visual deep-sky observing is not worth the effort here.

Nearby, there are limited upgrades in sky quality available. While some sites around 110 km north-north-west offer a noticeable improvement, they still fall short of true dark skies and should be approached with tempered expectations.

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

Limited nearby upgrade

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

Good dark window

Philadelphia'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 Philadelphia?

No. Philadelphia is a Bortle Class 9 sky with SQM 16.98, 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 Philadelphia?

Philadelphia is Bortle Class 9 (SQM 16.98), a severe urban sky for astronomy.

Is Philadelphia good for stargazing?

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

Is Philadelphia good for astrophotography?

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

What can you observe from Philadelphia?

Primary targets from Philadelphia 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 Philadelphia?

The closest meaningfully darker mapped site is 48 km ESE, about 48 km east south east of Philadelphia, reaching Bortle 6.

When is the sky darkest in Philadelphia?

The sky over Philadelphia is darkest around January, December.

Is light pollution in Philadelphia getting better or worse?

There is not yet enough long-term data to give a confident trend for Philadelphia.

• 48 km ESE

  Direction

  ESE

  Distance (km)

  47.7

  SQM

  19.86

  Bortle

  6

• 70 km SSE

  Direction

  SSE

  Distance (km)

  69.6

  SQM

  19.95

  Bortle

  6

• 96 km WSW

  Direction

  WSW

  Distance (km)

  95.6

  SQM

  19.85

  Bortle

  6

• 110 km NNW

  Direction

  NNW

  Distance (km)

  110.4

  SQM

  20.08

  Bortle

  6

• 121 km SW

  Direction

  SW

  Distance (km)

  121.4

  SQM

  20.21

  Bortle

  6

• 147 km NNE

  Direction

  NNE

  Distance (km)

  146.6

  SQM

  20.09

  Bortle

  6