Solar Parallax
the angle subtended by the radius of the earth at a distance equal to that of the earth from the sun. More exactly, it is the angle subtended by the equatorial radius of the earth at the mean distance of the sun, though this would be called, when speaking exactly, the mean equatorial horizontal parallax of the sun. It is, as nearly as we know it today, almost 8.8", with an uncertainty of probably not more than 0.01" or 0.02" different from this in either direction. This corresponds to a distance of the sun a little less than