The eagle is really high up there, and all by himself. So far up that it appears to be near the same height as the sun. (What's that, like 93 million miles or something?) OK, "close" is a relative term. If the earth and the sun are the two opposite poles of distance, than the eagle seems closer to the sun than to earth, which makes us wonder how the speaker can see the eagle so well, if it's so far away.