WEATHER UNIVERSITY: Afraid of the dark? Not much to fear these days

Another Barry Burgess masterpiece! Black Brook Falls, Cape Breton Highlands National Park at 3:16 a.m. June 17. Barry said that

What’s not to love about June? The sun is up before 5:30 a.m. and it doesn’t set until after 9 p.m.

Sunrise and sunset times are one thing, but when it comes to darkness and light, we should take into account the many shades of twilight.

There is astronomical twilight, known as partial darkness, after sunset or before sunrise, when the centre of the sun is between 12 and 18 degrees below the horizon.

Nautical twilight is that period in the morning and evening when the sun is between six and 12 degrees below the horizon.

Civil twilight: when the geometric centre of the sun’s disk is no more than six degrees below the horizon.

With all these twilights, how much true darkness is there these days? For an example, let’s use June 22 data for Charlottetown, P.E.I.

	Sunrise: 5:27 a.m.	Sunset: 9:08 p.m.
	Astronomical twilight	2:34 a.m. to 3:48 a.m.
	Nautical twilight	3:48 a.m. to 4:41 a.m.
	Civil twilight	4:41 a.m. to 5:20 a.m.
	Daylight	5:20 a.m. to 9:07 p.m.
	Civil twilight	9:07 p.m. to 9:46 p.m.
	Nautical twilight	9:46 p.m. to 10:39 p.m.
	Astronomical twilight	10:39 p.m. to 11:53 p.m.
	Night	11:53 p.m. to 2:34 a.m.

You’ll find total darkness in Charlottetown between 11:53 p.m. and 2:34 a.m. - a grand total of two hours and 41 minutes. Labrador City is plunged into total darkness for only one hour and 28 minutes. In Halifax, there is no light in the sky at all for three hours and 25 minutes.

June 22, 2018, data for Charlottetown, P.E.I.

Photographers like Barry Burgess take advantage of the soft light in the night sky to create stunning images. With milder nights on the way, why not give it a try?