Current Affairs Lower house passes "dark-sky law"

Light pollution On a clear moonless evening, we should be able to see more than 2000 stars in the sky. Today, in many urban areas, and even rural areas, there are often less than 100 stars visible in the night sky. This is because of wasted illumination spilled to the sky from poorly shielded outdoor light fixtures. Obtrusive outdoor lighting that shines visible glare severely diminishes our ability to see properly in the night time environment. What is the situation in the Czech Republic, a question I put to Petr Harmanec, director of the Astronomical Institute of Charles University.

"I think the situation with light pollution in the Czech Republic is relatively bad in the European context. You can see satellite pictures showing that the level of light pollution is very high over the whole territory of Bohemia and Moravia, the highest light pollution being in the central part of Bohemia and northern part of Moravia. Therefore I believe that it's good news both for astronomers and common people because, fortunately, our interests are the same in this respect, because better regulation of illumination by artificial light means that it helps drivers, old people and also, in a longer perspective, we shall be saving energy."

Telescope It can be dangerous if improperly aimed and unshielded light fixtures along roads shine bright light into drivers' eyes. Light pollution can also disturb our night's sleep when artificial illumination shines into our windows at night. And too much artificially generated light at night can even have adverse effects on our health by disrupting natural hormone production. But astronomers are very badly affected as well as light pollution greatly diminishes, if not completely removes the view of deep sky objects in the cosmos. Petr Harmanec agrees.

"Your observations get less accurate and we really have problems. I was in Ondrejov observatory last weekend and I was very upset seeing one laser show which comes from a restaurant. Every weekend you can see a laser show, lightening which goes all over the sky and it's completely spoiling the conditions and therefore the background for the observation is spoiled. So for us it's really an imperative to do something about that and we need legislation which would allow us to negotiate with such people and find some reasonable solution."

Supernova Despite ever deteriorating conditions for observation, Czech astronomers are quite successful on an international scale. For example, after five years of monitoring, they succeeded in proving that a very bright object was actually two stars, a phenomenon known as binarity. Three weeks ago, astronomers from Brno discovered the explosion of a so-called peculiar star, proving it was a Nova. Czech astronomy, says Petr Harmanec, is recognised around the world.

"In 2006 the International Astronomical Union, the largest organisation of professional astronomers in the world will have a general assembly in Prague. Another candidacy was offered by Canada and we won, which again tells you that Czech astronomy is somehow known and respected all over the world."