So recently the local Hampshire Council has been turning off local street lights at 1am and turning them back on at 4am. Now of course this was in a bid to reduce running costs but there is a positive to this change of heart.
Apart from the various benefits of darker nights such as better sleeping patterns for humans alongside a bat friendly environment then the benefits for astronomers cannot be understated.
We use a Sky Quality Meter from Unihedron in order to measure the seeing conditions and record it in the long exposure deep sky objects we try to image.
Below is the graph for the entire night of 8/9th September 2019 and the effect of bathroom light close by can be observed at around 21:20. This clearly demonstrates how bad local light pollution can be. By 4:30am the astronomical darkness window had passed and the SQM was dropping.
The effect of the new street light policy at 1am is obvious as an increase from a SQM reading from 20.4 to a maximum of 20.59 is observed until 4am when the street light came back on again and the sky quality immediately drops.
This places the local area as bortle class 4 ( 21.69–20.49) and a long way from a rural setting (21.69-21.89) or even Kielder Water (21.88) which can only get worse with more housing developments and unnecessary outdoor lighting.
So although we are grateful for improvement in the local dark skies it would be great to see the lights staying off for longer in winter so we can attempt to get better images. Hopefully we can start to come close to appreciate what people saw before the intrusion of unnecessary artificial lights in our life bloated out the wonders of the night sky without having to resort to traveling to the top of La Palma.