A panoramic view of stars setting on the western horizon as seen at the Equator, in Kenya. Because this is a long time-exposure, every star appears to set absolutely perpendicular to the horizon (the white horizontal line in the middle of the image. For stars near the Celestial Equator, (which is in the center of the image) their paths are not only perpendicular, but also a straight vertical line; but for stars well to the north (on the right in this image) or south (on the left in this image) the vertical line turns into a curved arc circling clockwise around the South Celestial Pole (beyond the left edge of the image) or counter-clockwise around the North Celestial Pole (beyond the right edge of the image). Turning to the left (or south) the stars' paths would be half-circles rising on the left and setting on the right), while turning to the right (or north) the stars' paths would be half-circles rising on the right and setting on the left). But no matter what direction you look, stars would rise and set perpendicularly relative to the horizon. (Image Credit LeRoy Zimmerman, apod021115)