Siding Spring Observatory is a proud supporter and neighbour of the Warrumbungle National Park - designated in 2016 as Australia's first International Dark Sky Park by the International Dark-Sky Association (IDA). Now, in 2018, the park boundary has been expanded to include Siding Spring Observatory.
An IDA International Dark Sky Park (IDSP) is a land possessing an exceptional or distinguished quality of starry nights and a nocturnal environment that is specifically protected for its scientific, natural, educational, cultural heritage, and/or public enjoyment.
The Gold Tier status of the site acknowledges the Warrumbungle National Park's pristine skies and reputation as an outstanding place to view the stars unfettered by the light pollution that affects Australia's cities.
Warrumbungle National Park joins other international parks such as Death Valley National Park in the United States and Galloway Forest Park in Scotland as officially designated Dark Sky Parks.
To protect the Observatory at Siding Spring from the cumulative impact of light, a critical light threshold has been determined. This is a measure of the maximum tolerable level of lighting in which astronomical observations can be made. The critical threshold is regularly monitored and used to guide assessment of cumulative impacts of artificial lighting associated with development.
The traffic light indicates the current light pollution conditions at Siding Spring Observatory as observed at zenith (immediately overhead).