[RightWhale]

all planets are in the same plane except Mecury, Earth, and Pluto

Pick a coordinate system and stick to it. Since we are on earth most of the time, we pick earth's orbit as the zero-zero. If we were on Mars we would pick Mars' orbit as zero-zero. Or, we could pick the plane of the sun's equator, which until recently was not known as precisely as earth's orbit. Pick one.

[ItsTheMediaStupid]

Pick a coordinate system and stick to it. Since we are on earth most of the time, we pick earth's orbit as the zero-zero. If we were on Mars we would pick Mars' orbit as zero-zero.

Did your respond to the wrong post, or do you need to take time to actually read? When did I say anything about which plane to identify as 0-0?