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East and West on the Sun

When we talk about East and West on the Sun the directions are flipped from what most people are used to: East is to the left and West to the right!

Why is this? When you look at a map or globe of the Earth you are basically imagining that you are floating above the Earth. If north is at the top then west is to the left and east is to the right.

When astronomers look at the sky we are doing the opposite: we are lying on the ground looking up towards the sky. In that case if we want north to be at the top of our map east has to be to the left and west to the right. This way west in the sky is on the same side as the western horizon of the Earth.

SOHO/EIT ultraviolet image of the Sun