File talk:Sidereal day (prograde).png

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Positions 1 and 2 should not be parallel[编辑]

The views from positions 1 and 2 would only be parallel if the planet's orbit were in a straight line perpendicular to the view. Since the planet is moving along an orbital arc, a full 360° rotation would have that view point slightly inwards. While I don't doubt that there must still be slightly more rotation (position 3) to point perfectly at the sun, it should be noted that the view at position 2 should have a slight angle downwards. --Adam Katz 19:15, 20 November 2007 (UTC)[回复]