Removing Light pollution Astrophotography Urban Astronomy

The moon and the stars no longer come to the farm. The farmer has exchanged his birthright in them for the wattage of his all-night sun. His children will never know the blessed dark of night.

 — Leslie Peltier in his autobiography

Urban night skies are rarely dark. Streetlights, billboards, and city glow create a thick orange haze that hides the stars and washes out the beauty of the night sky. Yet even from light-polluted locations, it’s possible to recover the natural tones of the night sky — with the right technique and patience.

Golden Bridge, Los Angeles – Before and After

Even in one of the brightest cities on Earth, the hidden beauty of the night sky can still be revealed. This composite image of the Golden Bridge in Los Angeles shows two worlds in one frame — the left half captures the harsh glow of urban light pollution, while the right half reveals what the same scene looks like after careful digital correction.

Light pollution Astrophotography Urban Astronomy

The difference is striking. On the left, the orange sky glow typical of large cities drowns out all but the brightest stars. On the right, subtle gradient removal and color correction bring back the natural depth of the night sky. No Milky Way is visible here — just the quiet, real sky above Los Angeles as it would appear without the interference of artificial light.

Photoshop Processing Steps for Light Pollution Removal

The following steps describe exactly how I processed the Golden Bridge image to reduce light pollution and restore the natural night sky appearance. This simple method can be repeated for other urban nightscapes.

Step1: Select the Layers panel and then  duplicate the layer

Step 2: Filter -> Noise -> Median… (about 50 px)
Step 3: Filter-> Blue -> Gaussian Blue… (about 30px)
Step 4: Select original layer
Step 5: Image -> Apply image (Blending: Subtract; Offset: 40)
Step 6: Delete the duplicate layer

In this photo, the digital cleanup was done using gradient-removal layers in Photoshop and subtle color balance adjustments. The goal wasn’t to create an unrealistic night sky, but to recover the true dynamic range that excessive lighting had hidden. The restored image shows a faint trace of the starry night rising over the bridge — a reminder that the night is never completely lost to light.

See also for example video in my other post: Comet 103P/Hartley 2 from New York City

Note, that Astronomy Tools has more sophisticated methods to remove light pollution, or you can do some variations of such methods (it depends from size of you original image). You also can apply it only for part of original image.

The other way to remove light pollution is using multiple images, see for example my other post: M42 Orion Nebula using iOptron SkyTracker in NYC

Why Light Pollution Happens

Light pollution occurs when artificial lights scatter in the atmosphere and overpower natural celestial light. Sodium and LED streetlights create broad orange or blue glows that spread for tens of kilometers, reducing contrast in photos and drowning out faint stars. For astrophotographers, it’s the biggest obstacle between the camera and the universe.

Preserving the Night Sky

As urban areas expand, the number of places with truly dark skies continues to shrink. Each successful image that recovers the stars from behind the glow is not just an artistic act — it’s also a message about preservation. Protecting our night environment helps both wildlife and human curiosity. After all, the sky is our oldest map of time.

Final Thoughts

Removing light pollution is part art, part science, and part patience. Whether working from a city balcony or a remote desert, every photographer can uncover the universe hidden behind the glow. The Golden Bridge image proves that even in the heart of Los Angeles, the stars are still there — waiting to be revealed.

Related Astrophotography Posts

• M42 Orion Nebula using iOptron SkyTracker in NYC
• Comet 103P/Hartley 2 from New York City
• The Solar Eclipse of April 8, 2024: An HDR Revelation of the Sun's Corona from Westport, New York
• Why the Equatorial Sky Glows More Red - My Nights Photographing Airglow in Tanzania and the Galápagos
• Topaz DeNoise AI Canon Ra Milky Way Astrophotography

Urban Astrophotography

These photographs demonstrate the challenges and possibilities of urban astrophotography under extreme light pollution in New York City. All images were taken from Brooklyn, where night skies are heavily affected by artificial lighting and fall into the Bortle Scale Class 9 (inner-city sky).

In the first image, photographed from my backyard at night, you can see a simple foreground of polls and a wire silhouetted against the sky. Above them are the Orion constellation and the Pleiades star cluster. The bright, washed-out background clearly shows the impact of severe light pollution, which reduces contrast and limits the number of visible stars.

Urban Astrophotography - NYC astronomy - Orion Constellation

The second image shows the Lyra constellation. Here, the urban foreground was minimized, allowing the stars themselves to stand out more clearly. I added constellation annotations in Photoshop to help identify the star pattern — a useful technique when imaging from bright city environments.

Urban Astrophotography NYC - Lyra Constellation

In the third image, the Cassiopeia constellation is visible, again with annotations added for clarity. Even under heavy light pollution, some prominent constellations can still be captured from Brooklyn, though only the brightest stars are detectable.

Cassiopeia constellation - Urban Astronomy-  Brooklyn Astrophotography

The final image is a panoramic night view of Manhattan photographed from Brooklyn Bridge Park. Both the Brooklyn Bridge (closer) and the Manhattan Bridge are visible, along with the illuminated Financial District and its reflections on the water.

Although a few bright points appear in the sky in this last image, they are not stars. Under Bortle Class 9 conditions, no recognizable constellations are visible above Manhattan. Most of these bright points are likely airplanes moving through the night sky rather than astronomical objects.

Brooklyn astronomy - Manhattan panorama at night

This post illustrates how urban astrophotography requires adjusted expectations — focusing on bright constellations, wide-field compositions, and creative framing — while also highlighting the dramatic contrast between natural night skies and the artificial glow of a major city.

Urban vs. Dark Sky: In heavily light-polluted cities like New York (Bortle Class 9), only first-magnitude stars are visible to the naked eye, while deep-sky objects are largely washed out by skyglow. In contrast, truly dark locations (Bortle Class 1–2), such as remote deserts or dark-sky parks, reveal a celestial masterpiece: thousands of stars, the full structure of the Milky Way, and faint nebulae and galaxies that are completely invisible from urban environments. The difference highlights how dramatically artificial lighting alters our human connection to the cosmos.

Related Posts

• Milky Way Casting Shadows – Chile (Bortle Class 1)
• Watching the Sky: Observing Meteors at Cherry Springs State Park
• Astrophotography: Tiny Planet at Night (Urban vs Travel Skies)
• Brooklyn at Night – City Light and Night Photography
• Grand Teton National Park Nightscape – Dark Sky Astrophotography

Brooklyn Astronomy - Andromeda Galaxy from Tripod

Astronomy? Impossible to understand and madness to investigate.

— Sophocles, c. 420 BCE

Brooklyn Astronomy -  Andromeda Galaxy from Tripod - Canon 40D

Zhumell 20x80mm SuperGiant Astronomy Binoculars

The Zhumell 20x80mm SuperGiant Astronomy Binoculars are impressive mainly because of their sheer size. An 80mm objective lens is enormous for binoculars and collects a surprising amount of light for wide-field astronomical observing.

In the photos below, the Zhumell 20x80mm binoculars are shown in two different setups. In some images, they are placed side-by-side with a Celestron NexStar 4SE telescope for direct size comparison. In others, the binoculars are mounted on a tripod, which is the typical configuration for stable wide-field observing. Together, these setups give a clear sense of both scale and practical use.

Zhumell 20x80mm SuperGiant Astronomy Binoculars and Celestron 4SE

Zhumell 20x80mm and Celestron 4SE

Unlike telescopes, large astronomy binoculars offer a wide field of view and natural, two-eye observing. With 20× magnification and large 80mm objectives, the Zhumell SuperGiants are especially effective for:

• Star fields and Milky Way scanning
• Large open clusters
• Bright nebulae under dark skies
• Casual lunar observing

SuperGiant Astronomy Binoculars

20x80mm SuperGiant Astronomy Binocular

ET Astrophotography - Astronomical Binocular and Super Moon

In the first photo, the binoculars are mounted piggyback on the Celestron NexStar 4SE, a setup I jokingly called the “Mickey Mouse setup.”

The NexStar 4SE’s automated tracking allows the binoculars to follow the sky smoothly, making it possible to observe wide fields without manually moving a heavy binocular mount. It’s simple, unconventional, and surprisingly effective.

Related Celestron NexStar 4SE Astrophotography

• Celestron NexStar 4SE Telescope with T-Adapter
• Saturn with NexStar 4SE and NexImage
• Celestron NexStar 4SE and Constellations