CURRENT STATUS OF THE NORMAN LOCKYER OBSERVATORY

  1.  The Norman Lockyer Observatory is situated one mile east of the coastal town of Sidmouth in East Devon and close to a south facing cliff-top on the "World Heritage Coast". It enjoys a relatively dark night sky with a southerly aspect across the sea. The observatory is about twelve miles from Exeter and ten miles from the M5 motorway.

  2.  The facility is a public access optical observatory maintaining some of the nation's most historic instruments, but it also provides modern telescopes with computer enhanced imaging. The Norman Lockyer Observatory Society is a registered charity (1048807) and holds the observatory under the terms of a lease from the East Devon District Council. The Society's principal charitable activities are the promotion of the "Public Understanding of Science and Technology" and support for science education in schools and universities. The preservation and improvement of the observatory's operating environment are important factors in its future success.

  3.  Sir Norman Lockyer built the observatory as a private venture in 1912 following closure of the South Kensington Observatory. It came under the control of the University of Exeter between 1946 and 1987 when it was used mainly for non-astronomical research projects. By the 1980s the observatory was almost derelict, but since its rescue by the East Devon District Council in 1988 it has developed steadily. It is now trying to complete funding for a further major expansion to cope with growing public interest.

  4.  There are few comparable public facilities in Britain that provide both a planetarium and a working optical observatory. The Times (Weekend 10 March 2001) listed the Norman Lockyer Observatory with the Greenwich Royal Observatory, the Edinburgh Royal Observatory, South Tyneside College, Jodrell Bank Radio Observatory and the Armagh Observatory and Planetarium as public access observatories in Britain. However, the Mills Observatory (Dundee) and the refurbished telescope at the Herstmonceux Science Centre should also be considered. Of these, we believe that only the Norman Lockyer and Armagh observatories are situated away from large cities.

  5.  There are many other smaller observatories operated by local astronomical societies for their members, but which occasionally make their facilities available to a wider public. A number of universities operate observatories in Britain for educational purposes. Some of these enjoy a relatively dark sky.

  6.  The Norman Lockyer Observatory is not funded by national or local government agencies nor receives on-going grants from any organisation. The Society has no endowments and needs to earn enough to maintain its instruments and pursue its charitable aims. In this respect it is similar to most astronomical societies in Britain, but is, perhaps, unique among the comparable larger observatories listed above.

  7.  The renowned research history of the Norman Lockyer Observatory lies in the analysis of star spectra. Its historic instruments are associated with Lockyer's pioneering work on star temperatures, which led to theories of stellar evolution and the foundation of the science of astrophysics. Spectral work on the heavens requires a clear sky without light pollution over the whole optical spectrum. The Observatory co-operates with undergraduate courses of Exeter, Plymouth and the Open Universities, and is available to any university for development projects.

LIGHT POLLUTION

  8.  The Observatory supports the "Campaign for Dark Skies" and is grateful for the work of the British Astronomical Association on its behalf.

  9.  The Norman Lockyer Observatory enjoys a relatively "clean" sky to the east and south across the sea. The atmosphere is usually free of chemical pollutants and, as the sea has a uniform temperature, the air is also free of rising currents that can distort optical images. However, the western sky is badly affected by light pollution caused by street lighting at Exeter. The expansion of this city, particularly the proposed new town at Broadclyst in East Devon, is a major concern. The Observatory suffers problems in the north from lighting in the Sidford area (one mile) and at Honiton (eight miles), which makes it difficult to use long exposure photography or conduct spectral work in this direction. However, it was possible to see and photograph a recent aurora. Aurora are almost unknown to most city dwellers and are very rarely seen from the South of England.

  10.  Broad-spectrum high-pressure sodium lanterns, used for lighting main roads, and white mercury streetlights, normally fitted in residential streets, produce most of the light pollution. Older lanterns are badly designed and are often badly aligned. Although the Observatory is able to remove the narrow lines of pure sodium light using optical filters, broadband light pollution makes work on the spectral content of starlight difficult.

  11.  An accelerated programme of streetlight replacement with modern lanterns, in which lamps are wholly recessed above the horizontal rim of the reflective shield, and also a requirement to fit these in all new housing developments would improve the local sky. The Observatory is grateful to lighting authorities for the recent replacement of street lamps along the A3052 at Clyst St Mary and Sidford.

  12.  Floodlit sports facilities, such as at schools in Exmouth, Ottery St Mary and Colyton, where lamps are tilted to project light forwards rather than down, seem difficult to correct without further compelling guidelines. The problem could be easily improved by adjusting lanterns so that all the light is directed downwards on to the playing area. Probably fewer lanterns could have been used with savings in cost and energy. Short of retrospective legislation to enforce correct adjustment, the slow drip of public education and persuasion seems our only hope of solution. The effect these maladjusted lights have on the vision of passing motorists also needs consideration if only on grounds of road safety. Floodlighting of buildings by ground sited lamps is a minor contribution to local light pollution around this Observatory.

ENERGY SAVING

  13.  The most pressing reason for a national programme to enforce good lighting practice is the saving in energy it could produce. Generating capacity might be reduced with consequent reduction of other pollutants. The Observatory is unable to provide detailed figures, but it believes claims by others that most existing outdoor lights shine up to 30% of their light energy directly into the sky. The predicted figure for energy saving needs independent review by a competent research organisation, but the Observatory believes that a high proportion of light energy now wasted could be prevented by a programme that ensures:

1.  The correct adjustment of existing lanterns.

2.  A programme of external lantern replacement on public buildings and floodlit areas with fittings that conform to a limit of no more than two per cent upwards light emission and powers to ensure that these are correctly aligned.

3.  A requirement that all new external light fittings sold for domestic use should conform to the 2% upward light emission limit and that manufacturers and stockists should provide clear and explicit fitting instructions.

4.  An accelerated programme of older streetlight replacement by energy efficient lanterns.

5.  A recommended preference for low-pressure sodium lamps on motorways, road junctions, railway marshalling yards and similar places where full colour perception is unnecessary.

6.  The earliest implementation of such programmes near working optical astronomical observatories.

  14.  The programme would permit use of fewer lanterns overall and/or lower power lamps and bring about a reduction of the UK's need for electricity generating capacity. These measures would help the UK to meet its reduction targets for dependence on fossil fuels. The improvement of the environment, including the enjoyment of the heavens, would be a valued outcome for all and British astronomers would also benefit.

3 March 2003