San Antonio Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

17.37

Bortle class

Class 9 (Class 9)

Darkness Quotient

18%

Dataset

April 2026

Inner city sky

San Antonio: The Practical Verdict

San Antonio, a major city in Texas, faces extreme light pollution due to its dense urban development and sizable population. Sky conditions here are classified as Bortle 9, rendering the Milky Way entirely invisible and significantly diminishing the visibility of faint astronomical targets.

From within the city, the most reliable observations include the Moon, planets, and brighter star clusters. Enhanced imaging using narrowband filters is still feasible but hampered by the bright sky background. Deep-sky observations of galaxies, nebulae, and meteor showers should be avoided as they are unlikely to yield satisfying results under these conditions.

For those seeking improved skies, travelling to Calhoun County, roughly south-east of the city, offers a major upgrade to Bortle 3 darkness, significantly enhancing the potential for deep-sky observing and widefield astrophotography.

At a Glance

Overall

Severe urban sky - This is a severely light-polluted urban sky. Only the Moon, planets, bright stars, and a few specialist targets remain practical.

Milky Way

Not visible - The Milky Way is not visible from this sky.

Best targets from here

Moon, planets, bright stars, double stars, solar system events, narrowband imaging only with care

Do not prioritise

visual deep-sky observing, broadband galaxies, reflection nebulae, widefield Milky Way

Best nearby upgrade

Calhoun County, Texas sits about 223 km south east and reaches Bortle 3, roughly 51x darker.

Good dark window

San Antonio's longest dark windows fall in December and January, with the shortest nights around June and July. Plan deep-sky sessions around the autumn and winter months for the best combination of long nights and true astronomical darkness.

Frequently Asked Questions

Can you see the Milky Way from San Antonio?

No. San Antonio is a Bortle Class 9 sky with SQM 17.37, so the Milky Way is not visible from the city. For Milky Way photography, look for a Bortle 4 or darker site.

What Bortle class is San Antonio?

San Antonio is Bortle Class 9 (SQM 17.37), a severe urban sky for astronomy.

Is San Antonio good for stargazing?

Not for serious deep-sky observing. San Antonio is a severe urban sky where the Moon, planets, and a handful of bright targets are the realistic options from the city itself.

Is San Antonio good for astrophotography?

Broadband deep-sky imaging is heavily compromised from San Antonio and a Bortle 4 or darker site is strongly recommended. Even narrowband imaging is difficult from San Antonio without careful processing.

What can you observe from San Antonio?

Primary targets from San Antonio include Moon, planets, bright stars, double stars, solar system events. Targets such as visual deep-sky observing, broadband galaxies, reflection nebulae are not realistic from this sky.

Where are darker skies near San Antonio?

The closest meaningfully darker mapped site is County Road 114, Texas, about 65 km east of San Antonio, reaching Bortle 6.

When is the sky darkest in San Antonio?

The sky over San Antonio is darkest around January, December.

Is light pollution in San Antonio getting better or worse?

Long-term light pollution over San Antonio has been broadly stable across the available measurements.

• County Road 114, Texas

  Direction

  E

  Distance (km)

  65.1

  SQM

  20.08

  Bortle

  6

• Davis, Texas

  Direction

  SSW

  Distance (km)

  71.5

  SQM

  20.02

  Bortle

  6

• Live Oak County, Texas

  Direction

  SSE

  Distance (km)

  149.6

  SQM

  20.85

  Bortle

  4

• FM 2441, Texas

  Direction

  SE

  Distance (km)

  143.3

  SQM

  20.64

  Bortle

  5

• Calhoun County, Texas

  Direction

  SE

  Distance (km)

  222.5

  SQM

  21.63

  Bortle

  3

• Wharton County, Texas

  Direction

  E

  Distance (km)

  194.7

  SQM

  20.48

  Bortle

  5