Generator
The eccentricity-shape generator
What an eccentricity does to the shape, and what it does to the offset
The fractional flattening 1 − b/a and the fractional focal offset c/a, against eccentricity. The offset is first order in e and the flattening is second, so at Earth's e = 0.0167 the outline is 0.014% from a circle while the Sun sits 1.67% of the semi-major axis off the centre — a factor of 120.
1 essay calls
eccentricity-shape. The drawing above is what it returns with no arguments at all; every
call below passes it something, because a placement that passes nothing draws whichever member
of the family the generator happens to default to rather than the one its essay argues about.
Where it is called
Every figure listed here is the same construction drawn at different numbers, so a correction to one is a correction to all of them.
