(Naturally) Vanishing Darkness

Up here in Scotland we’re entering that time of year when astronomers have to pretty much pack away their scopes until the skies darken again later in the year.

While it’s still possible to keep observing the Moon, planets, and brighter stars over the next month, in a few days time from my latitude in Glasgow, there will be no true darkness, with astronomical twilight stretching across midnight.

Further north, in Inverness for example, this has been the case for the last few days, while further south, in London, you won’t lose proper darkness at night until 24 May.

We won't quite see a midnight sun, but "Simmer Dim" is a feature of Scottish summer night skies

Tonight I can expect about an hour and a half of dark observing in central Scotland. Tomorrow night we’ll have about an hour, and on Wednesday night there will be a sliver of around 15 minutes! After that it’ll be astronomical twilight all night, until 03 June when we encounter that unique Scottish occurence known locally as “Simmer Dim”, when the night never gets as dark as astronomical twilight, with nautical twilight meaning a midnight blue-ish sky for a few weeks over midsummer.

At this time of year man-made light pollution takes second stage to natures own midsummer light show, at least up here in Scotland!