v2.1.0: expose sin/cos of hour angle on observer rather than hour ang…

…le (#15)
darkskyapp · Apr 8, 2019 · 474d3a9 · 474d3a9
1 parent edc21b1
commit 474d3a9
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Showing 2 changed files with 9 additions and 5 deletions.
diff --git a/lib/solar.js b/lib/solar.js
@@ -149,8 +149,9 @@ function sin_elevation(ms, lat, lon) {
 
 // Solar position classes. Helpful if you need to cache results!
 class Location {
-  constructor(hour_angle, sin_elevation) {
-    this.hour_angle = hour_angle;
+  constructor(sin_hour_angle, cos_hour_angle, sin_elevation) {
+    this.sin_hour_angle = sin_hour_angle;
+    this.cos_hour_angle = cos_hour_angle;
     this.sin_elevation = sin_elevation;
   }
 
@@ -190,9 +191,12 @@ class Time {
     const cos_lat = Math.cos(lat * RAD);
     const sin_dec = this.sin_declination;
     const cos_dec = Math.sqrt(1 - sin_dec * sin_dec);
+    const sin_hour_angle = Math.sin(hour_angle);
+    const cos_hour_angle = Math.cos(hour_angle);
     return new Location(
-      hour_angle,
-      sin_lat * sin_dec + cos_lat * cos_dec * Math.cos(hour_angle)
+      sin_hour_angle,
+      cos_hour_angle,
+      sin_lat * sin_dec + cos_lat * cos_dec * cos_hour_angle
     );
   }
 }

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "astro",
-  "version": "2.0.4",
+  "version": "2.1.0",
   "description": "Solar and lunar position calculations",
   "main": "index.js",
   "devDependencies": {