Cheltenham Stargazing & Astronomy Report

Key Sky Quality Metrics

SQM (mag/arcsec²)

19.37

Bortle class

Class 7 (Class 7)

Darkness Quotient

38%

Dataset

July 2026

Suburban/urban transition

Cheltenham: The Practical Verdict

Cheltenham, a small city nestled within Gloucestershire, suffers from high light pollution typical of urban settings. Stargazing here tends to be hindered by light, leaving most deep-sky observations infeasible. The significant limiting factor is the suburban light dome prevalent in the region, with the Milky Way realistically invisible.

When observing from Cheltenham, a variety of targets remain accessible. Bright celestial objects such as the Moon, planets, and double stars are prominent against the light-ridden backdrop. Open clusters and efforts at narrowband imaging, despite requiring careful processing, offer some solace to the enthusiast. However, deep-sky activities such as visual observation and broadband galaxy imaging should be avoided here.

For those seeking a darker sky, Bachaethlon, about a 100 km drive north-west, is a recommended alternative. This Bortle 3 site provides a marked improvement for deep-sky observing without a significant drive.

At a Glance

Overall

Poor urban/suburban sky - This is a poor sky for astronomy. The Moon, planets, and a few bright objects remain viable, but deep-sky work is difficult.

Milky Way

Not visible - The Milky Way is not realistically visible from this level of light pollution.

Best targets from here

Moon, planets, bright double stars, bright open clusters, narrowband imaging with careful processing

Do not prioritise

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

Best nearby upgrade

Bachaethlon sits about 98 km north west and reaches Bortle 3, roughly 6.5x darker.

Moderate dark window

Cheltenham's limiting factor is not only light pollution. Around midsummer, Cheltenham loses true astronomical darkness entirely, so deep-sky observing and imaging are strongly seasonal. Plan serious sessions around the darker months.

Frequently Asked Questions

Can you see the Milky Way from Cheltenham?

No. Cheltenham is a Bortle Class 7 sky with SQM 19.37, 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 Cheltenham?

Cheltenham is Bortle Class 7 (SQM 19.37), a poor urban/suburban sky for astronomy.

Is Cheltenham good for stargazing?

Not for serious deep-sky observing. Cheltenham is a poor urban/suburban sky where the Moon, planets, and a handful of bright targets are the realistic options from the city itself.

Is Cheltenham good for astrophotography?

Broadband deep-sky imaging is heavily compromised from Cheltenham and a Bortle 4 or darker site is strongly recommended. Narrowband imaging of bright emission nebulae remains viable from Cheltenham with appropriate Ha or OIII filters.

What can you observe from Cheltenham?

Primary targets from Cheltenham include Moon, planets, bright double stars, bright open clusters, narrowband imaging with careful processing. Targets such as visual deep-sky observing, broadband galaxies, reflection nebulae are not realistic from this sky.

Where are darker skies near Cheltenham?

The closest meaningfully darker mapped site is Langley, about 36 km east south east of Cheltenham, reaching Bortle 5.

When is the sky darkest in Cheltenham?

The sky over Cheltenham is darkest around January, December. Significant summer limitation: around 64 nights per year have no true astronomical darkness.

Is light pollution in Cheltenham getting better or worse?

There is not yet enough long-term data to give a confident trend for Cheltenham.

• Langley

  Direction

  ESE

  Distance (km)

  36.2

  SQM

  20.72

  Bortle

  5

• Sibford Ferris

  Direction

  ENE

  Distance (km)

  45.5

  SQM

  20.65

  Bortle

  5

• Chapmanslade

  Direction

  SSW

  Distance (km)

  75.8

  SQM

  20.94

  Bortle

  4

• Bachaethlon

  Direction

  NW

  Distance (km)

  97.8

  SQM

  21.40

  Bortle

  3

• Merthyr Cynog

  Direction

  W

  Distance (km)

  95.6

  SQM

  21.30

  Bortle

  3

• Kingsclere

  Direction

  SE

  Distance (km)

  86

  SQM

  20.61

  Bortle

  5