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Guildford Astronomical Society

serving sw surrey since 1955

Local Dark-Sky Sites

Image courtesy of Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center.http://eol.jsc.nasa.gov

You can see just how bad this from this Shuttle image.

Light pollution in the Guildford and the surrounding areas has continued to increase over the past ten years. Most of this can be traced to the increasing urbanization of this corner of Surrey.

To the south-west, Godalming is now a significant contributor, the west and north-west has suffered particularly badly with the development of the Blackwater Valley. Looking north, the light dome from Woking has effectively blanked out the northern skies. If that were not enough, the centre of London is only 35 miles away to the north-east.

Local Conditions

We have a few sites that we can recommend to other amateurs and sometimes use ourselves. On average nights, you can expect visual limiting magnitudes of 5.2-5.6 and on good nights, perhaps 5.8. Peter Dean has followed local conditions for the past 15 years and reports the following

  • In general, the best conditions for sky transparency occur when the prevailing wind is from the north west. I don't know why this is, it just is.
  • Alternatively, immediately following the passage of a cold front (which usually travels eastwards) dodge the clouds and maybe the showers too.
  • In summer, for deep-sky work you must observe on the first night following the onset of calm weather with clear skies. As calm conditions become established, conditions rapidly deteriorate due to vehicle pollution. On the second and third days, a brownish layer of vehicle-induced smog can be clearly seen ringing the horizon and the sky becomes increasingly milky. By the fourth day of such conditions, you can forget any deep-sky work whatsoever.

Nearby Sites

Puttenham Common

Puttenham common

Puttenham Common.

To the west of Guildford, there is Puttenham Common. (South car park) This is on the southern side of the North Downs, locally known as the 'Hogs Back', just off the A31. The Hogs Back to the north conveniently obscures the light pollution put out by the Blackwater Valley, although the glow from Farnham now lights up the north-west. Guildford to the east and north blots out this part of the sky. Where Puttenham really scores, is that it has clear unobstructed views to the south-east, continuing right round to the west. Looking out toward Hindhead in the south, there are just a few villages and no towns. As the common is extensively wooded with areas of scrub and heathland, local seeing is very stable. The only problem, if it can be called one, that of courting couples. Oh, and the occasional deer.

Albury Heath

Albury Heath

Albury Heath.

Observing at Albury Situated to the east of Guildford, Albury Heath is just off the A25, between the villages of Albury and Shere, on the southern side of the North Downs. The major problem here are the lights of Guildford to the west, although they are moderated somewhat by woodland. The glow of London to the north-east is highly apparent.

Like Puttenham, it has clear unobstructed views from the south-east right round to south-west. The Heath is extensively wooded with a few scattered areas of scrub and heathland. Courting couples are not a problem as this site is isolated. There is loads of room for parking and setting up. Access is by a 200 yard long side track, that is easy to miss from the road. At the time of writing, it is unpaved and there are many deep potholes. Drive slowly if you value your suspension.

Limiting magnitudes you can expect from this site are similar to Puttenham Common.