Light pollution is the main obstacle to astronomical observations in urban environments. Artificial light sources scatter in the atmosphere, brightening the night sky and obscuring stars, planets, and other celestial objects. In 2026, this issue remains pressing, as the majority of the population lives in cities, forcing astronomers to find ways to adapt and reduce the negative effects of external lighting.
Causes of Light Pollution in Cities
The primary sources of light pollution are street and architectural lighting, advertising signs, and building facade illumination. For example, in Russia, Moscow allocates about 12 billion rubles annually for street lighting, with roughly 40% of this light scattering into the atmosphere, failing to illuminate the ground as intended.
There are several recognized types of light pollution:
- Skyglow — light directed upwards that scatters in atmospheric layers.
- Glare — bright spots in the observer’s field of view caused by direct or reflected light sources.
- Diffuse light — light reflected from aerosols, dust, and moisture.
Impact of Different Light Sources
Halogen lamps and LED fixtures with varying spectra have different effects. Light with short-wavelength blue components scatters more, worsening sky visibility. Modern LED lamps from Philips and Osram, for instance, are produced with warm spectrums of 2700–3000 K, which reduces scattering and partially lessens light pollution.
How Light Pollution Degrades Astronomical Observations
Light pollution lowers sky contrast, making faint stars and objects invisible. In cities, the number of visible stars drops from a normal 3000 to hundreds or even tens.
For astronomers, this means longer exposure times, costlier equipment, and often the need to travel outside the city. For example, in Moscow, astronomers use Celestron NexStar 8SE telescopes equipped with filtering systems to partially counteract light pollution, but this is only a partial solution.
Technical Aspects
- 90% reduction in star visibility in large metropolitan areas
- from 50000 ₽ cost of light pollution suppression filters for amateur telescopes
- 15 km average distance to dark zones around cities suitable for quality observations
Methods to Minimize the Effects of Light Pollution
Modern technologies and regulations help reduce the impact of artificial lighting. Among them:
- Use of fixtures with directed light — prevents sky illumination.
- Application of warm LEDs with temperatures of 2700–3000 K.
- Implementation of standards and regulations for outdoor lighting, such as GOST R 54946-2020, which limits upward light flux.
- Automatic dimming or shutdown during nighttime (smart lighting systems).
Comparison of Popular Urban Lighting Fixtures
| Model | Color Temperature (K) | How Directed the Light Is (%) | Price (₽) |
|---|---|---|---|
| Philips UrbanStar 120W | 3000 | 85 | ~8000 |
| Osram Streetlight LED 150W | 2700 | 90 | ~9500 |
| Generic Halogen 150W | 4000 | 60 | ~3000 |
Choosing Telescopes and Accessories for Urban Astronomy
For city observations, it is recommended to select telescopes that support installation of light filters and electronic image correction. Popular models in 2026 include:
- Celestron NexStar 8SE — equipped with a built-in Light Pollution Reduction (LPR) filter.
- Sky-Watcher Evostar 80ED — a popular refractor with options for narrowband filter installation.
LPR and UHC filters effectively reduce glare from street lamps, allowing objects to appear 30–50% brighter on the surface.
The Role of Legislation and Public Initiatives
Since 2023, Russia has had a federal GOST regulating light pollution limits in cities, requiring fixtures with directed light and automatic brightness control. For example, in Moscow, over 60% of streetlights have been replaced since 2025 with LED models featuring warm light and directional control.
Public organizations, such as the Russian Amateur Astronomers Union, run campaigns to inform and promote responsible lighting practices.
Frequently Asked Questions
Why does blue light interfere with astronomy more?
Is it possible to completely eliminate light pollution in cities?
Which filters are best for urban astronomy?
How far from the city is needed for quality observations?
Key Takeaways
- Light pollution reduces star visibility in cities by more than 90%.
- Warm LED fixtures reduce atmospheric scattering and minimize skyglow.
- Using LPR and UHC filters improves the quality of astronomical observations under urban light pollution.
- Modern legislation and technology enable effective reduction of light pollution in Russian cities.
- For quality observations, astronomers often need to travel 15 km or more beyond city limits.
Light pollution remains one of the major challenges in 21st-century astronomy, especially amid urbanization. However, a combination of technological solutions, effective legislation, and societal awareness about lighting can significantly improve nighttime observation capabilities in cities. By choosing the right equipment, fixtures, and filters, and supporting initiatives to reduce glare, we can reclaim the beauty of the night sky even in large metropolitan areas.
Sources
- What Is Light Pollution? — “Light Pollution”
- svetzavod.ru — “Why Stars Are Invisible in Cities: Main Causes and Solutions”
- rambler.ru — “Light Pollution in Russian Cities: How It Harms Insects, Birds, and Our Sleep — Rambler/Saving Together”
- Mir Kosmosa — “Light Pollution — Category Publications”