The angle, in degrees, between the horizon and the object.
Since Calgary is north of the Tropic of Cancer, the maximum
altitude of the sun or moon will always be above the south
The angle, in degrees, measured clockwise from north to the
point on the horizon where the object appears.
The instant when the object passes over the observer's meridan.
Since Calgary is north of the Tropic of Cancer, this will be the
instant when the sun or moon is due south.
In the above listings, actually Civil Twilight.
When the sun is within 6° of, but below, the horizon.
During Civil Twilight, there is generally sufficient illumination
to carry on outdoor activities. Nautical Twilight
(not shown above) is when the sun is within 12° of the
horizon and means that outlines are generally visible.
Astronomical Twilight (not shown above) is when the
sun is within 18° of the horizon and means that the sun is
contributing to sky illumination.