Fix EP2

Author: bkeepers

packages/tide-predictor/src/constituents/EP2.ts

@@ -3,14 +3,10 @@ import nc from "../node-corrections/index.js";
 
 /**
  * Lunar elliptic semi-diurnal constituent (ε2).
- * Doodson Number: 256.555
- * From Moon's elliptical orbit; speed 29.6°/h with period of ~12.0 hours.
  * Uses M2 nodal factors (fM2/uM2) for amplitude and phase modulation.
  *
- * Note: Sometimes called ν2 variant in some sources, but IHO designation is definitive.
- *
  * @see https://iho.int/en/standards-and-specifications/standards/s-14 IHO Tidal Constituent Bank
  * @see https://tidesandcurrents.noaa.gov/ NOAA CO-OPS constituent tables
  * @see https://en.wikipedia.org/wiki/Theory_of_tides Theory of Tides
  */
-export default defineConstituent("EP2", [2, 0, 1, 0, 0, 0, 0], nc.uM2, nc.fM2);
+export default defineConstituent("EP2", [2, -3, 2, 1, 0, 0, 0], nc.uM2, nc.fM2);

packages/tide-predictor/test/constituents/index.test.ts

@@ -40,7 +40,7 @@ describe("Base constituent definitions", () => {
 
   it("has correct properties for EP2 (lunar elliptic semi-diurnal)", () => {
     expect(constituents.EP2).toBeDefined();
-    expect(constituents.EP2.speed(testAstro)).toBeCloseTo(29.025, 2);
+    expect(constituents.EP2.speed(testAstro)).toBeCloseTo(27.4238338, 7);
     expect(constituents.EP2.u(testAstro)).toBeCloseTo(constituents.M2.u(testAstro), 2);
     expect(constituents.EP2.f(testAstro)).toBeCloseTo(constituents.M2.f(testAstro), 3);
   });