From df736cf0a0fa3e577f2c3a90214ce23ec6ec7902 Mon Sep 17 00:00:00 2001
From: michealroberts <michael@observerly.com>
Date: Fri, 9 Aug 2024 12:29:12 +0100
Subject: [PATCH] feat: add calculateB to vsop87 module in
 @observerly/astrometry

feat: add calculateB to vsop87 module in @observerly/astrometry
---
 src/vsop87.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/vsop87.ts b/src/vsop87.ts
index 765131e..076e40f 100644
--- a/src/vsop87.ts
+++ b/src/vsop87.ts
@@ -29,3 +29,17 @@ export function calculateL(τ: number, terms: { A: number; B: number; C: number
 }
 
 /*****************************************************************************************************************/
+
+export function calculateB(τ: number, terms: { A: number; B: number; C: number }[][]): number {
+  let B = 0
+
+  for (let i = 0; i < terms.length; i++) {
+    const b = calculateTerms(τ, terms[i])
+    B += b * τ ** i
+  }
+
+  // The result must be converted from 1e-8 radians to radians and then to degrees:
+  return degrees(B / 1e8)
+}
+
+/*****************************************************************************************************************/