SUMMARY RESPONSE TO THE FIVE QUESTIONS RAISED BY THE COMMITTEE

  1.  The effect of light pollution on optical observational astronomy has been disastrous. What the UK climate makes difficult, light pollution has made all but impossible, even with the advent of CCD detectors, for most parts of the UK.

  2.  Current planning guidelines are insufficient to protect against light pollution. Light Trespass is not recognised under UK law. The only ground for formal protest is the environmental impact of the height of the standards. A planning inspector can be sympathetic—giving ride, in favourable cases, to some amelioration.

  3.  Planning Guidelines on outdoor lighting hardly exist, but where a planning application makes reference to lighting issues, an observatory can often be informed and consider representation to the planning enquiry. But such information may not be consistently passed on by a planning office and there is evidence for disregard of any restrictions of use imposed in the planning grant.

  4.  Light Pollution is measurable, the appropriate design of luminaires is defineable and consequential regulatory control could be enforced.

  5.  Control of outdoor lighting design is highly desirable—especially in regard to security lighting, lighting of areas used for sport and decorative outdoor lighting. The Commission Internationale d'Eclairage has adopted a lighting zoning system which forms the basis for the International Dark-skies Association's Model Lighting Ordinance—now in the trialing phase.

  Not covered by the Five Questions

  There is now movement towards opening the Optical and InfraRed frequency space to communications use. The International Telecommunications Union is now looking at allocation of these frequencies. Astronomy has enjoyed the use of optical frequency space for millenia and the infrared for decades without hindrance. Should telecommunications take over the optical and infrared for transmission, then optical and infrared astronomy, worldwide, would be imperilled by the footprints of communications laser beams.

1.  INTRODUCTION

  In 1999 the United Nations (UN), through its Committee on the Peaceful Uses of Outer Space (COPUOS) held a major space event—UNISPACE III (Vienna, 1999 July 19-30)—to examine in depth the achievements of the exploitation of space—both scientifically an commercially. The international astronomical community were invited to participate in order to present their concerns on, inter alia, the degradation of astronomical observing conditions by activities in space. The presentation took the form of a symposium organised by the International Astronomical Union (IAU) (Preserving the Astronomical Sky, IAU symposium no 196, ed Cohen and Sullivan, ASP 2001). The Symposium forwarded a resolution to the UN. (A/CONF.184/C.1/L.2) which was favourably received by the UN. Astronomical concerns were specifically mentioned in the UN Vienna Declaration summarising the outcome of UNISPACE III (A/CONF.18416—Report of the Third UN Conference on Exploration and Peaceful Uses of Outer Space). Resolution one of that document urges consideration of the consequences of space activities which could adversely affect astronomy, Earth observation and remote sensing. This issue was further amplified in section G, paragraph 73, of the Report, the last sentence reading "Attention should be given to preserving or restoring astronomical observing conditions to a state as close to natural as possible by any possible means." Given the high commercial return on investment in the exploitation of space, this support for maintaining the astronomical observing environment to that determined by natural processes is very significant. It will cost a considerable sum to maintain the astronomical observing environment. The UN's attention was focussed on space activities, not ground based activities which produce light pollution at optical and infrared frequencies. Light Pollution at ground level is, nevertheless, a very serious degradation of the astronomical observing environment. It is not the only degrading factor—there are others—ground vibration from industrial and transportation processes, molecular and particulate pollution of the atmosphere, electromagnetic noise at radio frequencies (the radio equivalent of light pollution), the proliferation of highly reflecting objects in space and their debris, radio and light emissions of aircraft, cloudiness indiced by aircraft contrails and the consequences of global warming. The astronomical community is beset by the activities of others adversely impacting their scientific endeavours. One of the characteristics of science is that the conditions pertaining in any scientific laboratory are systematically controlled by the scientists who use them, so that the conditions specific to the location of the laboratory have minimal impact on experimentation. The astronomical community is necessarily denied that advantage: they can only accept the natural limitations imposed by observing from the bottom of the Earth's atmosphere or from space; they have to accept that the legitimate activities of others will impact on the quality of their "laboratory". This is, in part, why astronomers have retreated to remote sites for optical, infrared and radio astronomy. Only recently have the adverse activities of others had such a degrading effect on astronomical observing conditions to the extent that the efficiency of use of astronomical instrumentation is being unacceptably compromised ie there are cost implications for astronomy resulting from the activities of other parties. Up to now astronomy has had no redress.

  To give some idea of the state of things in the UK, from calibrated measures of the upward flow of man made light, Cinzano, Falchi and Elvidge (Monthly Notices, Royal Astronomical Society) demonstrate that 85% of the area of the UK experience sky glow at a level above natural sky background, that 100% of the UK population experience a sky background in excess of the natural background level and that 40% of the UK population experience a sky background in excess of nine times the natural background. For the USA the corresponding percentages are 62%, 99% and 62%.

  The effect of light pollution in the UK is not so much on the professional astronomer, though the world wide proliferation of light pollution is a very serious concern. The effect is on astronomical education. Astronomical education is the principal sufferer—all university observatories must be close to their parent universities for convenient access—this means such universities will suffer from urban light pollution. Young people will not be aware of astronomy as a university discipline unless they can see the sky and be inspired by it scientifically, The role of the amateur astronomer in assisting young people to go beyond the star gazing stage and begin to think about astronomy quantitatively and scientifically cannot be too heavily emphasised (a role which Sir Patrick Moore has played—very unobtrusively). Would be astronomers need to practice their astronomical skills and become conversant with what is possible and what is not possible with the technology of their time. Without access to the sky, such training is negated. In the 70's photographic imaging of extended objects could not be profitably pursued at the University of London Observatory—only in the 90's with CCD's could such imaging be resumed. Specialisation in spectroscopy was a good but partial response.

  The focus of the Select Committee is on Light Pollution in the UK and the remainder of this submission will address this issue by treating the questions raised by the Select Committee in order.

2.  QUESTION 1

  Light Pollution is not new, but has become a rapidly increasing problem for Astronomy worldwide. It is essential that streets are well lit during the hours of darkness, that security is maintained and that essential activities can be carried out at night in safety. Even with the best lighting design, light spill must occur. However, current light spill is excessive, unnecessary to achieve the avowed aims of outdoor lighting and a major single waste of power, and by association, light spill contributes to the atmospheric carbon burden.

  Light spill has two components—direct illumination beyond the area for which the lighting was "designed" and upward escape of light to be scattered downwards by atmospheric particulates trapped by the inversion layers—giving rise to sky glow. Direct illumination occurs when an observatory is situated near the sources of light. It is usual to site observatories well away from sources of light. For example, the University of London Observatory was situated at Mill Hill in 1928 as a compromise between distance from the lights of London and accessibility from University College London. Worries were expressed at the light spill from Hampstead at the time! The Observatory was accessed by means of a country lane—now a six lane major highway that is the Barnet Bypass: all that was not country lane was built on Observatory land. (Like many urban observatories the University of London Observatory was built on land available at a notional rent from a public spirited civic body. Now the Observatory is caught in a financial trap—it cannot afford to move to a better site—if that were possible while retaining convenient access for students.) The Barnet Bypass is now lit to major dual carriageway standards—the Observatory is a classic example of direct light pollution. Parallel histories are to be found for the Cambridge University Observatories and the Norman Lockyer Observatory at Sidmouth. None of these observatories can afford to move—and indeed—would a move at great expense be useful given the spread of urban lighting schemes—the further one is from England the nearer one is to France. Direct lighting is inevitable as urban centres expand. The lack of planning guidelines for outdoor lighting has exacerbated this situation (see next section).

  Light escaping sideways and upwards from ill designed luminaires gives rise to sky glow. Escaping light is scattered in the atmosphere by particulates and by the inversion layers—particularly the first. Light from a wide area contributes to sky glow. Sky glow has two components of which the principal one is light escape; the second is the quantity of atmospheric particulates. The quantity of atmospheric particulates can be reduced by rain, but dry weather leads to rapid restoration of the numbers of particulates. To reduce sky flow both light escape and particulate reduction are important.

  Unlike protection of astronomical observing conditions in space, reduction of light pollution has economic advantage. There is no point in allowing up to 30% of light for a particular task to illuminate the sky. Lighting engineers can routinely design lighting schemes which put the light where it is needed—on roads, sports facilities, architectural masterpieces and provide security and safety to users of those facilities while providing sufficient illumination for the purpose. Modern road lighting schemes, viewed from above, present an illuminated ribbon of road: poor road lighting schemes present an illuminated ribbon of road and clear visibility of each and every lamp used. If upward escape of up to 30% of light emitted upwards is cut out, less power is needed to fulfil the purpose of the lighting. Yet more power could be saved if the lighting used no more power than was essential to fulfil the aims of the lighting scheme—often a significant amount less than currently used. Use of less power means less carbon burden in the atmosphere. I estimate that the UK minimally maintains 500MW of generating capacity to illuminate the sky at night for street lighting alone. More quantatively, Isobe (Preserving the Astronomical Windows, ASP, 1998) estimates that in 1997 an area of 2,030 sq km around central London emits upwards of 29 million KWh each year from all sources of outdoor lighting. As an order of magnitude suppose 1KWh costs five pence, this means London spends upwards of gbp145 million annually fruitlessly illuminating the sky. Spending over the entire country must exceed gbp one billion. For comparison: Paris, over an area of 2,091 sq km emits 38 million KWh, Vienna, over an area of 1,080 sq km emits seven million KWh. Even Tucson, Arizona—a city with considerable commitment to astronomy, over an area of 1,804 sq km emits 13 million KWh annually upwards. If the UK could reduce the burden of inessential light emitted upwards, a saving of just under 1% of the total energy consumed annually by the UK could be attained.

  Good lighting design is the key to the problem. This is achieved in many major public lighting projects. However, the proliferation of poorly designed, overly powerful, security lighting is on the increase—often installed solely on the advice of Crime Prevention Officers. Outdoor lighting is now a feature of many gardens. Some is well designed and at a level which cannot be easily criticised; most, however, is unsatisfactory eg illuminated globes which are a singularly ineffective way of providing illumination as 1/4 pi of the available light goes in any one direction and the light is not concentrated on specific features and thus maximises the effect of the inverse square law.

  The colour of outdoor lighting is as important as its intensity. Low pressure sodium lamps are economical of spectrum use, having virtually all their output confined to a narrow range of frequencies in the yellow. This can cause difficulties with colour recognition—however, the addition of a very little white light can rectify that situation when essential. Coincidently but fortuitously, low pressure sodium makes a highly efficient lamp. Other lamps eg mercury, quartz, tungsten filament, all make substantial demands on spectrum use. From the astronomical point of view, the spectral frugality of low pressure sodium lamps make them the lamp of choice. Spectroscopy is the one key area of astronomical research which is least sensitive to light pollution provided outdoor lighting restricts its use of spectral range rigorously.

  There is a general view of the more light the better. From the point of view of visibility, security and dark adaption, there is considerable evidence that lower levels of outdoor lighting would enhance, and not diminish these factors. It is beginning to be realised that the elderly take longer than average to dark adapt, that glare reduces visibility and that creation of deep shadow may decrease personal security. From, personal experience, I am aware that I benefit from improvement of visibility where street lighting is present but at low level, being caught suddenly in the full glare of a security light harms my dark adaption for about a minuit—enough not to be aware of a lurker in deep shadow. A well thought out scheme, based on actual operation of the human eye and not on the myth of the brighter the better, coupled with quality lighting design, could mean significant reduction in light pollution to the benefit of society more generally, and not just the astronomical community.

3.  QUESTIONS 2, 3

  The planning authorities in the UK are not empowered to consider the effects of outdoor lighting. The environmental impact of the lighting supporting structures is covered eg the height of the standards. There is no code of practice on the intensity or spectral nature of any proposed lighting. With time, energy and dedication one might prove nuisance eventually. A sympathetic planning inquiry inspector may be able to get a compromise eg I objected on behalf of the University of London Observatory to a proposal by the Mill Hill Tennis Club to illuminate their courts so that tennis could be played during the evenings. Eventually agreement was reached on a design which allowed minimal light escape, saved the Club money on running costs and established a time for lights out. Both the Observatory and the Tennis Club benefit thereby. However, good planning guidelines might have produced an effective design initially and saved considerable hard talking. At the moment the essential guidelines, if any, do nothing to protect against light pollution. Often where a lighting restriction is placed, it is ignored and the restriction is not enforced. There is a situation of this nature currently affecting the Norma Lockyer Observatory.

  If good guidelines did exist, it would be of assistance in the vast majority of instances of outdoor lighting. If a lighting design had to certify that it met the planning rules on lightspill horizontally and vertically before planning consent could be given, it would be a great step forward. It would also help if the use of security lighting were addressed with proper rules and lightspill standards to be met and brought within the planning consent framework, in the effort to reduce light pollution. This would require careful investigation of good practice in a range of situations and need proper definition of the output and spectral quality of the lamps/luminaires.

4.  QUESTION 4

  Lighting Engineers are capable of measuring spectral quality and intensity of lamps and the geometrical parameters for the output from luminaires. This is not may area of expertise and therefore improper for me to attempt to go further. I can however, speak of my admiration for the skill and expertise that has gone into many recent lighting schemes—especially of those football stadia which, when observed from above. Show only an illuminated pitch and show minimal lightspill. Good lighting design leaps out when seen from a low flying aircraft and I commend such a trip to the Select Committee.

5.  QUESTION 5

  Further controls on the design of lamps, luminaires and the design of lighting schemes will be essential to produce effective reductions in light pollution. Today anyone can buy and install outdoor lighting without reference to anyone. That the result may be glare for pedestrians and motorists using pathways and roads or unwanted illumination of neighbours' gardens or bedrooms is currently of little account in the planning or legal process. Light Trespass is not a concept in UK law. This situation may need rectification.

  The International Dark-Skies Association (IDA) has produced a Model Lighting Ordinance based on the Commission Internationale d'Eclairage (CIE) zoning model. The CIE model indicates the amount of light required to give proper visibility at night in downtown, suburban and urban areas with a view to minimising lightspill and glare. The Ordinance endeavours to construct a code of practice, legally enforceable, for outdoor lighting of all classes. The Ordinance has been drawn up with the assistance of lighting engineers, town planners, legal authorities in order to find a comprehensive way forward to reduce light pollution. Currently the Ordinance is undergoing trial—the most advanced of which is an ordinance for East Vancouver. While this is a highly North American approach it has great potential from an astronomical point of view as well from the energy saving perspective. It may not translate comformably to a country like the UK where light trespass is not recognised as a problem. It is something the select Committee might care to investigate further with the IDA.

6.  CONCLUSION

  Reduction of light pollution can bring many benefits—the public can enjoy the lost spectacle of the heavens, the astronomer can better utilise the facilities of the educationally orientated urban astronomical observatories, considerable power saving can be attained thus making a significant contribution to the atmospheric carbon burden and certain wildlife benefits will accrue. We all stand to gain from reduction of light pollution. But above all the science of astronomy can continue its exciting studies of the Universe using the unparalled tools provided by a vibrant 21st century technology.

15 April 2003