[KegRiver]

Very interesting. And it is part of our history.

I grew up in a class one zone and now live in a class three zone.

Originally Posted by Crankbait

bit of a derail but interesting nonetheless. while trying to find a picture of the sign post at starland recreation area I was linked along to this. Apparently the campground rates a 4 on this chart but has anyone noticed that the glow of Calgary from the outskirts of the city is much duller since they switched to the new lights? maybe why I can see the northern lights from in the city limits now.

John Bortle's Light Pollution Scale

John Bortle Scale Alberta Night Skies

John Bortle created the light pollution scale. Pollution Map . Show Light Pollution In Your Location

A class 1 excellent dark sky, is something you'll never forget. Very few individuals have ever witnessed one. Finding a location with no light pollution is becoming a thing of the past. Not more than 100 years ago the night sky was completely visible. The milky way could be viewed from one horizon to other.

With more than half of the world’s population now living in cities, 3 out of every 4 people have never experienced the wonderment of pristinely dark skies. Thankfully some our national parks are starting to take action against light pollution by establishing dark sky preserves. Light pollution has a negative effect on the worlds ecosystems and our wildlife, especially migrating song birds. Jasper National Park seems to be leading the way on this issue by promoting dark sky events and restricting the use of artificial lightning and inefficient light fixtures.

Several of the campsites shown on AlbertaWow indicate the Bortle light scale number for it's location. Also see Attilla Danko's Night Sky Prediction Charts and Dark Skies Awareness



Class 1: Excellent dark-sky site - Black
The zodiacal light, gegenschein, and zodiacal band are all visible - the zodiacal light to a striking degree, and the zodiacal band spanning the entire sky. Even with direct vision, the galaxy M33 is an obvious naked-eye object. The Scorpius and Sagittarius region of the Milky Way casts obvious diffuse shadows on the ground. To the unaided eye the limiting magnitude is 7.6 to 8.0 (with effort); the presence of Jupiter or Venus in the sky seems to degrade dark adaptation. Airglow (a very faint, naturally occurring glow most evident within about 15 degrees of the horizon) is readily apparent. With a 32-centimeter (12½) scope, stars to magnitude 17.5 can be detected with effort, while a 50-cm (20-inch) instrument used with moderate magnification will reach 19th magnitude. If you are observing on a grass-covered field bordered by trees, your telescope, companions, and vehicle are almost totally invisible. This is an observer's Nirvana!

Class 2: Typical truly dark site - Gray
Airglow may be weakly apparent along the horizon. M33 is rather easily seen with direct vision. The summer Milky Way is highly structured to the unaided eye, and its brightest parts look like veined marble when viewed with ordinary binoculars. The zodiacal light is still bright enough to cast weak shadows just before dawn and after dusk, and its color can be seen as distinctly yellowish when compared with the blue-white of the Milky Way. Any clouds in the sky are visible only as dark holes or voids in the starry background. You can see your telescope and surroundings only vaguely, except where they project against the sky. Many of the Messier globular clusters are distinct naked-eye objects. The limiting naked-eye magnitude is as faint as 7.1 to 7.5, while a 32-cm telescope reaches to magnitude 16 or 17.

Class 3: Rural sky - Blue
Some indication of light pollution is evident along the horizon. Clouds may appear faintly illuminated in the brightest parts of the sky near the horizon but are dark overhead. The Milky Way still appears complex, and globular clusters such as M4, M5, M15, and M22 are all distinct naked-eye objects. M33 is easy to see with averted vision. The zodiacal light is striking in spring and autumn (when it extends 60 degrees above the horizon after dusk and before dawn) and its color is at least weakly indicated. Your telescope is vaguely apparent at a distance of 20 or 30 feet. The naked-eye limiting magnitude is 6.6 to 7.0, and a 32-cm reflector will reach to 16th magnitude. Long exposure astrophotos might show some light pollution gradient, but visual observing is relatively unimpaired.