From Mr Michael Gainsford

Sir: It was gratifying to see that the menace posed by light pollution to our night skies is at last being recognised ("Seeing stars - if only we could", 4 September).

However Jonathan Glancey was rather unfair in laying the blame at the door of street lighting engineers. The Institution of Lighting Engineers's new guidelines are aimed at the prevention of emission of light above the horizontal, and street lighting authorities, in this area at least, are aware of the problem and are doing something about it. However it will take many years to change over all lighting units to the new standards.

The greatest threat is from private lighting - so-called "security lights", neon adverts, lasers, floodlights, and the globe lights beloved of architects. Over these there is little control, although a growing number of planning authorities are attempting to remedy this, including clauses in local plans. But without clear guidelines and encouragement from central government this is bound to be a very slow process. Despite lip-service to the need to save energy, Mr Gummer is oblivious to the vast amount of energy wasted in needlessly lighting up the sky.

In the United States things have become so bad that the 100in Mount Wilson telescope can no longer be used professionally, and several states have now enacted strict laws preventing stray light, particularly in areas near observatories.

Yours faithfully,

Michael Gainsford

Burbage, Leicestershire

4 September

The writer is Leicester officer for the British Astronomical Association's Campaign for Dark Skies.