Pasadena Stargazing & Astronomy Report
Light pollution and stargazing locations near Pasadena
- City
- Pasadena
- Country
- United States
- Latitude
- 34.1478
- Longitude
- -118.1445
Key Sky Quality Metrics
- SQM (mag/arcsec²)
- 17.59
- Bortle class
- Class 9 (Class 9)
- Darkness Quotient
- 20%
- Dataset
- March 2026
Inner city sky
Pasadena: The Practical Verdict
Pasadena is a historic city in Southern California, set against the foothills north-east of central Los Angeles and known for its scientific institutions, grand architecture and dense urban setting.
The city generally experiences Extreme Light Pollution, with a Darkness Quotient of 20% — placing it among the most light-polluted urban locations in the United States.
For practical observing from within the city, the most reliable targets are the Moon, planets, double stars and the brightest open clusters. Faint deep-sky objects are heavily washed out by the urban skyglow, with only a few of the very brightest nebulae or globular clusters showing with patience.
Meaningfully darker skies do not appear close to hand, and a proper improvement requires a substantial drive out of the Los Angeles basin. The nearest reasonable dark-sky step up is about 95 kilometres to the east-south-east, near Near Kern County, California, where conditions reach Bortle 4.
The map shows Pasadena embedded within a very large, intensely bright urban core, with the central area rendered in pinks and whites that indicate severe skyglow. That bright zone spreads broadly across the surrounding metropolitan area, so Pasadena does not stand out as an isolated hotspot so much as part of one continuous, highly illuminated conurbation.
Around the city, the colours shift outward through red, orange, yellow and then green, showing that brightness eases only gradually rather than dropping away quickly. The most noticeable darker regions lie farther out to the north, north-east and east, while the south and south-west remain tied into the wider urban glow for longer.
Overall, the map suggests that Pasadena is brighter than almost all of its immediate surroundings, but only by degree rather than by kind: the whole region is strongly lit. For observers, that means escaping local street lighting alone is not enough — you also have to get well away from the broader metropolitan light dome to find a real change in sky quality.
Overhead sky impression
Looking straight up from Pasadena, the sky is strongly affected by urban light, with a zenith reading of 17.59 and an inner-city level of brightness. Even overhead, where the sky is usually darkest, the background remains bright enough to suppress much of the fainter star field.
The familiar brighter constellations still come through, but they tend to look thinned out, with only their main pattern stars standing out clearly. The Milky Way is effectively lost from the city sky, and much of the visual experience is dominated by the brighter naked-eye objects.
For casual observing this still leaves plenty to enjoy, especially the Moon and planets, but the overhead view is a reminder that Pasadena is operating under one of the brighter urban skies.
north - marginal
About 15 kilometres north of Pasadena, the sky is still only marginal, around Bortle 6, so urban glow remains obvious. Conditions do improve further out, and genuinely dark skies are reachable in this direction at about 200 kilometres.
north-north-east - marginal
Around 15 kilometres to the north-north-east, conditions are marginal at Bortle 6, with some improvement over the city but still plenty of skyglow. A much better result appears farther out, with good dark-sky territory emerging by about 200 kilometres.
north-east - marginal
At roughly 15 kilometres north-east, the sky is still marginal at Bortle 6, so brighter targets remain the sensible focus. If you keep going, substantially darker skies become available at about 200 kilometres in this direction.
east-north-east - poor
About 15 kilometres east-north-east of the city, the sky remains poor at Bortle 7, with heavy light pollution still dominating the view. This direction does improve with distance, and genuinely dark skies show up at about 200 kilometres.
east - poor
Around 15 kilometres east of Pasadena, the sky is still poor at Bortle 8, with very limited improvement over the city itself. Conditions get better much farther out, but genuinely dark skies are not reached within the sampled distance in this direction.
east-south-east - poor
At roughly 15 kilometres east-south-east, conditions are poor at Bortle 9, so the urban glow is still overwhelming. There is improvement farther out to around Bortle 4 by the edge of the sampled range, but genuinely dark skies are not reached within the sample radius in this direction.
south-east - poor
About 15 kilometres to the south-east, the sky remains poor at Bortle 9 and is still heavily washed out by metropolitan light. It does improve with distance to around Bortle 4 farther out, but genuinely dark skies are not within the sample radius in this direction.
south-south-east - poor
Around 15 kilometres south-south-east of the city, the sky is still poor at Bortle 9, with little practical relief from light pollution. This direction improves only modestly, and genuinely dark skies are not within the sample radius.
south - poor
At roughly 15 kilometres south, the sky is poor at Bortle 9, so only the brightest celestial targets stand out well. The picture changes much farther out, with genuinely dark skies appearing at about 200 kilometres.
south-south-west - poor
About 15 kilometres south-south-west, conditions are poor at Bortle 9 and still deeply affected by the city's light dome. A major improvement comes only with a long journey, with genuinely dark skies reached at about 200 kilometres.
south-west - poor
Around 15 kilometres south-west of Pasadena, the sky remains poor at Bortle 9, among the brightest quick-drive directions from the city. It improves significantly farther out, with genuinely dark skies available at about 200 kilometres.
west-south-west - poor
At roughly 15 kilometres west-south-west, the sky is still poor at Bortle 9, so deep-sky observing remains very limited. A substantial improvement is possible with distance, and genuinely dark skies are reached at about 200 kilometres.
west - poor
About 15 kilometres west, conditions are poor at Bortle 8, with bright skyglow still prominent. This direction eventually becomes much better, but genuinely dark skies are only reached at about 200 kilometres.
west-north-west - poor
Around 15 kilometres west-north-west of the city, the sky is poor at Bortle 8, with only a modest gain over central Pasadena. It does become much darker farther out, with genuinely dark skies appearing at about 200 kilometres.
north-west - poor
At roughly 15 kilometres north-west, the sky is poor at Bortle 8, so the wider urban glow is still very much in control. There is some improvement farther out, but genuinely dark skies are not reached within the sampled distance in this direction.
north-north-west - marginal
About 15 kilometres north-north-west, the sky is marginal at Bortle 6, offering one of the better nearby directions but still far from dark. This is one of the more promising corridors outward, with genuinely dark skies reached at about 100 kilometres.
zenith - poor
Looking straight up from Pasadena, the overhead sky is poor, with Bortle 9 conditions and an SQM of 17.59. The brighter constellations are still recognisable, but many fainter stars disappear into the glow and the sky has the washed-out look typical of a bright inner-city environment.
-
Near Inyo County, California
- Direction
- SE
- Distance (km)
- 306.4
- SQM
- 21.64
- Bortle
- 3
Milky Way visible, broadband DSO imaging
-
Near Kern County, California
- Direction
- NNW
- Distance (km)
- 117.1
- SQM
- 21.03
- Bortle
- 4
Bright nebulae, galaxies, narrowband imaging
-
Near Kern County, California
- Direction
- ESE
- Distance (km)
- 92.6
- SQM
- 20.88
- Bortle
- 4
Bright nebulae, galaxies, narrowband imaging
Historical Light Pollution Trends
Pasadena's sky has shown a slight long-term brightening trend over the available record. The SQM has moved from 17.78 in the earliest reading to 17.59 in the latest one, a modest decline in darkness over time.
Across 76 datasets, the average reading is 17.75, with values ranging from 17.59 to 17.96. The trend slope is gentle rather than dramatic, but it still points in the wrong direction for urban stargazing.
In practical terms, this means Pasadena has remained consistently very bright for many years, with only small fluctuations from one period to another. Observers in the city should expect heavily light-polluted conditions to be the norm rather than the exception.