Round Rock Stargazing & Astronomy Report

Light pollution and stargazing locations near Round Rock

City
Round Rock
Country
United States
Latitude
30.5083
Longitude
-97.6789

Key Sky Quality Metrics

SQM (mag/arcsec²)
18.14
Bortle class
Class 8 (Class 8)
Darkness Quotient
24%
Dataset
March 2026

City sky

Round Rock: The Practical Verdict

Round Rock is a fast-growing suburban city in Central Texas, just north of Austin, with a distinctly metropolitan edge despite its own strong local identity.

The city generally experiences High Light Pollution, with a Darkness Quotient of 24% — making it brighter than good rural observing areas and placing it among more light-polluted urban locations. For practical observing from within the city, the most reliable targets are the Moon, planets, double stars and the brightest open clusters. Fainter deep-sky objects are heavily washed out by the city glow, with only a few showpiece objects managing to punch through under good transparency.

Meaningfully darker skies are not close at hand from Round Rock. The nearest reasonable step up is about 100 kilometres to the south-south-east, near Gonzales County, Texas, where conditions improve to a genuinely useful rural sky.

The map shows Round Rock sitting within a broad, intense urban lighting zone, with bright white-pink cores and surrounding red and yellow spill blending into a larger metropolitan glow. This pattern suggests that local sky brightness is driven not just by the city itself but by the wider built-up region around it.

The darkest tones in the crop lie mainly to the west and north-west, where the colours fall away through blue into dark grey and black, indicating a much cleaner sky background away from the urban core. By contrast, the south, south-east and east remain heavily affected by scattered bright patches and extended glow, so Round Rock is clearly brighter than much of its western side but closely tied to a larger network of illuminated settlements in other directions.

Overall, the map gives the impression of a city with one notably darker escape corridor, especially toward the west to north-west, while several other directions stay compromised by overlapping light domes for a long distance.

What the sky overhead is like

Looking straight up from Round Rock, the zenith is still firmly city-bright rather than truly dark. At 18.14 SQM and Bortle 8, the overhead sky will usually show the brighter constellations, but with reduced contrast and fewer faint stars than you would see from the countryside.

The familiar patterns of the seasons remain recognisable, and bright stars and planets stand out well enough for casual observing. What is largely missing is background richness: the Milky Way is effectively lost, and the sky tends to have that softly luminous urban look rather than a deep black appearance.

north - poor

Fifteen kilometres north of Round Rock, the sky is still poor for stargazing, remaining at Bortle 8. It does improve with distance, but even far out in this direction the best sampled conditions only reach Bortle 5, so genuinely dark skies are not available within the sampled radius.

north-north-east - poor

At about 15 kilometres to the north-north-east, conditions are still poor, around Bortle 7. The glow eases gradually farther out, but the best sampled sky in this direction only reaches Bortle 5, so it never becomes truly dark within the sampled range.

north-east - poor

Fifteen kilometres north-east, the sky is still poor at Bortle 7, though it is clearly improving compared with the city centre. Farther out this becomes a much more promising route, reaching Bortle 4 by around 50 kilometres and staying relatively good beyond that.

east-north-east - poor

Around 15 kilometres east-north-east, the sky remains poor at Bortle 7. This direction improves strongly with distance, reaching good rural conditions by around 50 kilometres and genuinely dark skies at roughly 200 kilometres.

east - poor

At 15 kilometres east of Round Rock, the sky is still poor, sitting at Bortle 7. Conditions do improve to a good rural sky around 50 kilometres out, but genuinely dark skies are not reached within the sampled radius.

east-south-east - poor

Fifteen kilometres east-south-east, the sky is still poor at Bortle 7. There is a worthwhile improvement to good rural conditions by around 50 kilometres, but genuinely dark skies only remain out of reach in the sampled area, and the far distance in this direction becomes much brighter again.

south-east - poor

Around 15 kilometres to the south-east, conditions are still poor at Bortle 8. The sky improves only gradually at first, with the more meaningful step up not arriving until much farther out, where it reaches Bortle 4 around 100 kilometres away.

south-south-east - poor

Fifteen kilometres south-south-east, the sky remains poor at Bortle 8. This direction improves substantially with a longer drive, reaching Bortle 4 around 100 kilometres out, which matches the nearest named dark-sky option near Gonzales County, Texas.

south - poor

At 15 kilometres south of the city, conditions are actually still very bright, at Bortle 9. This is not a good quick-escape direction, although much farther out it does recover to a useful rural sky, reaching Bortle 4 at around 200 kilometres.

south-south-west - poor

Around 15 kilometres south-south-west, the sky is poor and heavily affected by urban glow, at Bortle 9. Improvement is slow in this direction, and while it eventually reaches Bortle 5 farther out, genuinely dark skies are not available within the sampled radius.

south-west - poor

Fifteen kilometres south-west of Round Rock, the sky is still poor at Bortle 8. It becomes somewhat better with distance, but the stronger improvement does not arrive until much farther out, with Bortle 4 only appearing around 200 kilometres away.

west-south-west - poor

At 15 kilometres west-south-west, the sky is still poor at Bortle 8. This is a strong long-distance direction, though: it improves to Bortle 4 around 100 kilometres out and reaches genuinely dark Bortle 3 skies at roughly 200 kilometres.

west - poor

Fifteen kilometres west of the city, conditions are still poor at Bortle 8. However, this is one of Round Rock's better escape routes, with genuinely dark skies appearing by around 100 kilometres.

west-north-west - poor

Around 15 kilometres west-north-west, the sky remains poor at Bortle 8. This direction improves very well with distance, reaching genuinely dark skies at about 100 kilometres and becoming even darker farther out.

north-west - poor

Fifteen kilometres north-west, the sky is still poor, around Bortle 7. It is one of the more promising directions overall, though, improving to Bortle 4 by around 50 kilometres and reaching genuinely dark skies at about 100 kilometres.

north-north-west - poor

At roughly 15 kilometres north-north-west, the sky is still poor at Bortle 7. With a longer drive this becomes much more rewarding, reaching genuinely dark skies at around 100 kilometres.

zenith - poor

Looking straight up from Round Rock, the zenith is poor for dark-sky observing, at Bortle 8. The brighter constellations are still easy enough to trace, but the sky background is luminous, faint stars are suppressed, and the Milky Way is effectively absent from view.

  • Near Bosque County, Texas
    Direction
    NE
    Distance (km)
    148.7
    SQM
    20.99
    Bortle
    4

    Bright nebulae, galaxies, narrowband imaging

  • Near Colorado County, Texas
    Direction
    SE
    Distance (km)
    151.5
    SQM
    20.96
    Bortle
    4

    Bright nebulae, galaxies, narrowband imaging

  • Near Gonzales County, Texas
    Direction
    SSE
    Distance (km)
    100
    SQM
    20.91
    Bortle
    4

    Bright nebulae, galaxies, narrowband imaging

Historical Light Pollution Trends

The long-term trend points to a gradual brightening of the night sky over time. The earliest reading in the series was 18.54 SQM, while the latest is 18.14 SQM, a decline of about 0.40 SQM across the record.

That change is modest rather than dramatic on a year-to-year basis, but it does indicate that the background sky has become a little brighter overall. With 76 datasets in the time series and a mean of 18.41 SQM, Round Rock appears fairly consistent in remaining an urban-bright sky, with only limited variation between its best and worst measurements.