No doubt you will have received amply technical and scientific evidence about the problems posed to visual astronomy by light pollution and also, perhaps, the increasing difficulties also experienced by radio astronomers about interference on other wavelengths. I can only add some amateur observations.

  My interest here arised as the owner of a 10 inch Newtonian reflecting telescope which I use from a suburban back garden here in North Oxford and more generally as someone who enjoys the beauty of the night sky and the subtleties of the darkness of the night-time environment out of doors.

  The astronomical problem is easily stated: it is quite clear, even without any measurement, comparing suburban Oxford with remoter places that visibility of the heavens is greatly impaired in suburban Oxford compared with remoter places. Deep-sky objects with low surface brightness—nebulae and galaxies—are especially hard hit. Depending on conditions, many of the objects described in popular astronomical guides as being "easy binocular objects" are very difficult or completely impossible to find and only the brighter stars can be seen with the naked eye. I know this is not primarily because of bad eyesight because I can see them under other conditions.

  It may seem, as it were, to be blindingly obvious that cities are brighter than the country. But the present scale of the problem is not inevitable.

  It has at last two major causes both capable of being moderated. The first is over-enthusiastic and inappropriate street lighting. Some of this in Oxford is so bright that it can cause discomfort when driving. "Improvements" in street lighting—ie brighter lights—are encouraged by a response to fear of crime (as was the case locally where I live, partly due to student hysteria based on no evidence at all) which does not seem to be very scientific. No doubt others have drawn your attention to the evidence—I think from the US—that brighter lights do not deter crime. Certainly the only muggings here ever—in the last couple of years—have occurred in broad daylight. And my neighbour's alloy wheels were removed from his car one night by the light of his security lamp. New lighting standards imposed by or on local authorities are often cited as the reason for brighter lights. Perhaps some of this is motivated by concerns about crime.

  May I suggest first that the justifications for brighter lights (crime, traffic safety) should be given closer scientific scrutiny than perhaps they may have received so far and the technical standards for lighting revised, if necessary, as a result.

  The second point concerns the design of street lights. Given that some lighting is clearly essential, a great deal is wasted by being broadcast upwards and sideways. The simplest modification of the design would seem able to focus the light where it is wanted—on pavements etc. That would also save money, as lights of lower wattage could be used for the same effective illumination. The overall saving could be very large. That would not just protect the narrow interests of astronomers. It would prevent glaring street lights shining into windows and or giving unwelcome illumination (as in my case) to front and back gardens—particularly unpleasant given the harsh sodium-vapour colour which replaced the more friendly blue-white mercury vapour in our area some years ago.

  Security lights are a rapidly growing problem. These are often of astonishing power and flood an area with light which is much bigger than that which needs to be protected. They can cause all sorts of problems. In our street alone one neighbour had difficulty sleeping because of a bright light opposite; one of the colleges has equipped its property with lights (permanently on) which shine in the face of motorists at a T-junction. Many private houses have these things now and institutions, especially Colleges and the University are particularly fond of them. I find it annoying to be lit up by a bright light when walking on the pavement past houses so equipped.

  Part of the problem arises from careless orientation—much can be done by making them point downwards. They are also, in many cases, excessively bright. And as with street lights the design does nothing to keep the light from scattering. And some are left on all the time. For example, the University here has equipped its houses in Bradmore Road with particularly hideous orange lights which are permanently on, and some colleges have done the same in Crick Road. St Anthony's College has such bright lights around it that at night it looks more like an outpost of the Gulag.

  A code of practice or a stronger code of practice, is needed here. I wonder also if it would be possible to imagine an entitlement akin to privacy, to prevent one's own property being lit up by someone else's light.

  Some of these comments do not relate directly to astronomical problems, of course. But I suggest that the inconvenience to astronomers is just one symptom of a broader issue of excessive illumination which does all sorts of harm to the night-time environment—essentially tending to abolish it—as well as wasting energy.

25 April 2003