Steve Tonkin is the Dark Sky Advisor to Cranbourne Chase National Landscape, in Wiltshire.  Cranbourne Chase is a designate Area of Outstanding Natural Beauty that, since 2019, has been recognised as an International Dark Sky Reserve.Steve can pinpoint 4 October 1957 as the first became aware of dark skies.  His family were, at the time, living 8 miles outside Bulawayo, Zimbabwe and his father took him outside to see if they could see Sputnik which had been launched the previous day.  It was his first time looking up at a pristine dark sky and it triggered a life-long passion for astronomy which has made him aware of the effects of light pollution, and he has been raising the issue with anyone who will listen for the last 30 years.After a first career as a telecommunications engineer, he did a BSc in Human Environmental Studies, then postgraduate work in technology policy, before training as a teacher. He taught physics, maths and astronomy in a variety of settings for 35 years, before retiring from teaching to concentrate on astronomy outreach activities. He has written several books on practical astronomy, has a monthly column in BBC Sky at Night Magazine, and is a regular speaker on astronomical topics.Starting with a programme he made for BBC Radio Bristol in the 1980s, Steve has long been an advocate of reducing light pollution.  He supported the Cranbourne Chase’s International Dark Sky Reserve bid as a volunteer, taking sky quality readings and supporting the stargazing evenings by giving talks and showing people the night sky. His primary task as Dark Skies Advisor is to continue and consolidate the good work that has already been done and strengthen the Cranbourne Chase’s standing as an International Dark Sky Reserve.Light pollution is a global issue.  The pollution itself is known to affect human health and wildlife behaviour and that is before considering the wasted energy involved in sending light upwards instead of downwards to where it is required.  To take a Biophilic approach to the design of lighting is to reduce light pollution with direct and indirect benefits to nature.Steve explains that there are 21 International Dark Sky Reserves across the world that have been recognised as being of distinguished quality.  He explains that these spaces are not about no lights but about the right light in the right place at the right time to preserve the area for heritage, educational and enjoyment purposes.Dark skies are relative.  A truly dark sky is defined by Steve as one in which the Milky Way galaxy casts a shadow.  In the context of Cranbourne Chase, it means the ability to see the Andromeda galaxy with the naked eye.  Steve expresses his excitement at being able to see something that is 2.5 million light years away and has been visible to earth since before humans were even around and was visible to all humans ever until light pollution started to be introduced 200 years ago.Steve explains in some detail why it is important to take account of the circadian rhythm of light and darkness and how there is always a negative effect of introducing artificial light.  He discusses the impact on the reproductive cycle of birds and relates that 8 to 10 million birds a year are killed by lit communication towers.Moving to humans, Steve tells of studies linking light pollution to  ·      increased susceptibility to cancer;·      increased incidence of obesity, diabetes and hypertension due to the impact of poor lighting on leptin levels (leptin being the hormone that tells you if you feel full); ·      the impact of the wrong sort of light on mental and physical health; and ·      the huge reduction in insect life (both pollinators and composters) and its impact on food production.Across a wide range of examples Steve explains how the wrong light can have disastrous consequences.  He introduces the idea that not all light is the same and sets out what to look for in order to achieve healthy lighting.Steve enumerates the five