// OBSERVATION NETWORK
OBSERVING CONDITIONS
Check current sky conditions, explore light pollution across the Rio Grande Valley, and find the information you need before heading outside to observe.
26.2200° N // 98.1200° W
Rio Grande Valley, TX
STARS // ONLINE
WEATHER
NIGHT SKY
LIGHT POLLUTION
BROWNSVILLE, TX
RECEIVING CURRENT WEATHER DATA...
Analyzing cloud cover, humidity, wind and visibility.
Live regional weather layers centered on your observation point. Hourly forecast appears in the metrics above.
FIND DARKER SKIES
Explore artificial sky brightness across the Rio Grande Valley and beyond to identify darker locations for astronomical observing.
WHAT THE COLORS MEAN
ARTIFICIAL SKY BRIGHTNESSThis map uses zenith sky brightness, the brightness of the sky directly overhead, measured in magnitudes per square arcsecond (mag/arcsec²). Higher numbers mean darker skies. Lower numbers mean brighter skies affected by artificial light.
HIGHER VALUESBRIGHTER SKIES
LOWER VALUES
HOW TO READ IT: Black and gray indicate the darkest sky backgrounds; blue and green show increasing skyglow; yellow, orange, red, purple and white indicate progressively brighter skies. This color key follows the legend supplied from LightPollutionMap.info. Readings describe modeled or mapped sky brightness, not a direct measurement of Bortle class.
THE BORTLE SCALE
CLASSES 1—9The Bortle Scale is a nine-class system for describing night sky darkness, from exceptionally dark locations (Class 1) to heavily light-polluted inner-city skies (Class 9). It describes what an observer can see, rather than measuring a single light source. Transparency, weather, moonlight and local glare can all change the view.
Exceptionally dark; the Milky Way is richly detailed, and faint sky features may be visible to experienced observers.
The Milky Way is highly structured, with very little artificial skyglow.
The Milky Way remains prominent; some distant light domes may be noticeable.
The Milky Way is still visible, but light pollution increasingly affects the horizon and faint detail.
The Milky Way is weak or washed out; brighter constellations and planets are easier to see.
Much of the Milky Way is invisible to the unaided eye; the sky background is noticeably bright.
Only brighter stars are easily visible; faint deep-sky objects become difficult to observe.
Many constellations are incomplete to the naked eye; the Moon, planets and brightest stars dominate.
Severe skyglow; typically only the Moon, planets and a limited number of bright stars stand out.
IMPORTANT: These swatches help distinguish the nine classes in this guide. They are not a direct lookup table for the map image's colors. A location's actual Bortle class must be assessed under suitable observing conditions.
FINDING A BETTER OBSERVING SITE
Look for areas away from dense development and major road lighting. A darker map region is a starting point, not a guarantee of access.
For faint galaxies, nebulae and the Milky Way, choose a moonless night or a time when the Moon is below the horizon.
Cloud cover, humidity, haze and smoke can limit observing even at a dark site. Use the STARS Sky Planner alongside this map.
Use legal public access, respect private property, travel safely and protect night vision with dim red lights.
EXPLORE TONIGHT'S SKY
Check this month's night-sky highlights, celestial events and observing guides from The Cosmic Current.
SEARCHING COSMIC CURRENT ARCHIVE...
Receiving the latest monthly astronomical events guide.