1.  What has been the impact of light pollution on UK astronomy?

  Light pollution has had a deleterious effect on UK astronomy. Britain's seriously light-polluted skies cannot sustain professional optical astronomy with large aperture telescopes. We adduce the removal of the Isaac Newton Telescope (INT), of 2.5 metre aperture (98 inch) aperture, from the Royal Greenwich Observatory, Herstmonceux, Sussex, to the Observatorio del Roque de los Muchachos, La Palma, Canary Islands, where it commenced operating in 1984.

  This was necessitated by the poor seeing conditions experienced in the UK because of sky glow—the consequence of light pollution.

2.  Are current planning guidelines strong enough to protect against light pollution?

  No. Present planning guidelines are inadequate and ineffective in dealing with light pollution. Guidelines only provide guidance for those who wish to comply; the force of law is necessary to ensure compliancy by all. By way of example there are no planning constraints on domestic security lighting, usually of the 500W unshielded type, and these cause considerable glare and light trespass onto adjacent property. These luminaires also emit light above the horizontal, ie skywards, thus exacerbating sky glow.

  In relation to planning matters and lighting in general, council planning departments tend to be sympathetic to the aims of the British Astronomical Association's Campaign for Dark Skies (CfDS) in reducing light pollution, but reiterate, that councils can only apply existing planning legislation. It is the professional opinion of planning officers who have joined this debate that present planning laws do not adequately address the lighting issue.

3.  Are planning guidelines being applied and enforced effectively?

  The answer to the previous question, particularly the professional view of planning officers, would suggest that the guidelines are ineffective in dealing with lighting controls.

  Example: The floodlighting at the 34-bay driving range at Mearns Castle Golf Academy, which is situated within East Renfrewshire, has been the subject of serious complaint by residents of houses up to four miles away from the golf range. These lights are causing glare and light trespass, yet planning permission had been obtained.

4.  Is light measurable in such a way as to make legally enforceable regulatory controls feasible?

  Yes. While this is a technical issue and could best be answered by the Institution of Lighting Engineers (see attached ILE Guidance Notes for the Reduction of Light Pollution), the Upward Light Ratio of a luminaire is measurable.

  A simple requirement of any future light-control legislation would be that only full cut-off (FCO) and semi cut-off (SCO) luminaires could be used. The old type of unshielded low pressure sodium (LPS) street light (the cause of much light pollution) would therefore be phased out and could only legally be replaced by modern "sky-friendly" FCS and SCO luminaires.

  A lighting engineer has informed the CfDS that his plans for a replacement road lighting scheme, utilising high pressure sodium (HPS) SCO luminaires, was overruled by his council superiors on cost grounds. The result—relighting by LPS unshielded luminaires of the "polluting" type—because they were cheaper! It should be noted that these replacement luminaires are expected to last for some 30 years, so no "quick fix" here. (The council concerned in this instance claims to have a "sky-friendly" lighting policy.)

5.  Are further controls on the design of lighting necessary?

  Yes. All luminaires should, in the case of road lighting, comply with British Standard specifications, viz, BS5489.

  Globe (isotropic) lighting should be fitted with hemispherical caps in order to prevent upward light emissions.

  Exterior floodlighting of buildings should preferably be by "downlighting"; where "uplighting" is used these uplighters should be properly aligned and baffled to prevent "searchlight beams" in the night sky.

  Any luminaires which cause glare, light spill and trespass, and/or emit light above the horizontal, should be illegal.

  The test of the efficacy of present policies on lighting control is simple: are our urban skies light-polluted or not?