There are many organisations with initiatives related to dark skies:
The International Dark-Sky Association (IDA) is the world authority on light pollution and is the leading organisation combating light pollution to protect the night skies for present and future generations. Its goals are to:
International Dark Sky Reserves (designated by the IDA) are public or private land of at least 700 km², accessible to the public in part or whole, that are legally protected for scientific, natural, educational, cultural, heritage and/or public enjoyment purposes. The core area must provide an exceptional dark sky resource, relative to the communities and cities that surround it, where the night sky brightness is routinely equal to or darker than 20 magnitudes per square arc second (http://darksky.org/idsp/become-a-dark-sky-place). Buffer zones help support dark sky preservation in the core.
Reserves are formed through partnerships of land managers who recognise the value of the natural night-time environment through regulation and long-term planning. The Brecon Beacons and Snowdonia National Parks have International Dark Sky Reserve status.
International Dark Sky Parks are similar to Dark Sky Reserves but are smaller areas and owned largely by one or two organisations. Examples in the UK are Elan Valley Estate (Wales), Galloway Forest (Scotland), Northumberland National Park (England) and Kielder Water & Forest Park (England).
The UK Dark Sky Discovery Partnership is an Non government Organisation network of national and local astronomy and environmental organisations, plus local communities, who aim to:
Dark Sky Discovery Sites are a nationwide network of places that provide great views of the night sky and which are accessible to everyone. They have been nominated by local groups and organisations and designated by the UK Dark Sky Discovery Partnership. In order to qualify for Dark Sky Discovery Site status, the locations need to meet a number of criteria that make them safe and accessible as well as having suitably dark skies. Dark Sky Discovery Sites are places that:
A map of Dark Sky Discovery Sites can be viewed at: http://www.darkskydiscovery.org.uk/dark-sky-discovery-sites/map.html
The Commission for Dark Skies is part of the British Astronomical Association (BAA), a non-government organisation (NGO) with national membership, which is concerned about the rapid increase of light pollution across the UK. The Commission has hundreds of members from a wide range of disciplines. Its aims are:
Greater use of modern fittings which control the light emitted and warm colour temperature light sources, to minimise sky-glow and light trespass.