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Credit: E. Wiebe

Late summer sunrise seen from Mt Tolmie in Saanich, BC (part of Greater Victoria) on 25 August, 2015. Mt Baker, faintly visible immediately to the left of the sun in the image, is about 72 from north when viewed from Mt Tolmie, so we know the sun is still on its southward journey through the morning sky. The sun will rise due east close to the autumnal equinox, on the 24th and 25th of September.

If you watch the sun's appearance at successive sunrises or its altitude at noon every day you notice it moves through the course of a year. This motion is due to the obliquity of the Earth, the angle of its rotation axis with respect to the plane of its orbit around the sun. It is this tilt, close to 23.4° which remains pointed at the same place in the wider universe as the Earth orbits the sun (hence the north star) that gives us our seasons and changing daylight time spans at latitudes more distant from the equator.

At southern Vancouver Island's latitude of 48.5° the sun will rise as far north as 52° and as far south as 126° (due east is 90°). As a point of comparison, at Fairbanks, Alaska (64° latitude) the sun rises as far north as 15° and as far south as 155°. This means that Fairbanks experiences much longer days in the summer and much longer nights in the winter.

Wikipedia on Earth's axial tilt, its obliquity.




UVic / SEOS / Climate Group / About Front Page Picture / Late Summer Sunrise Last updated: Tuesday, 01-Sep-2015 09:09:39 PDT
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