add julian calendar

YingChangJ · May 1, 2024 · 4b93207 · 4b93207
1 parent 5112bcb
commit 4b93207
Showing 1 changed file with 42 additions and 5 deletions.
diff --git a/javascript/julian.js b/javascript/julian.js
@@ -77,12 +77,14 @@ function updateTime() {
   date.setUTCFullYear(yearForCal);
   date.setUTCHours(date.getUTCHours() - timeZoneForCal);
   const astroTime = new Astronomy.AstroTime(date);
-  console.log(astroTime);
+
   utInput.value = (astroTime.ut + 2451545.0).toFixed(6);
   ttInput.value = (astroTime.tt + 2451545.0).toFixed(6);
   tsInput.value = +date;
   tssInput.value = Math.floor(date / 1000);
-  jde.innerHTML = `JDE (J2000): ${astroTime.tt.toFixed(6)}`;
+  jde.innerHTML = `
+  Julian Calendar(UTC): ${jd2JulianCalendar(astroTime.ut + 2451545.0)}
+  <br>JDE (J2000): ${astroTime.tt.toFixed(6)}`;
 }
 
 function updateTimeFromTT() {
@@ -101,7 +103,10 @@ function updateTimeFromTT() {
   tt.value = astroTime.tt + 2451545.0;
   ts.value = +dateNew;
   tss.value = Math.floor(+dateNew / 1000);
-  jde.innerHTML = `JDE (J2000): ${astroTime.tt.toFixed(6)}`;
+  jde.innerHTML = `Julian Calendar(UTC): ${jd2JulianCalendar(
+    astroTime.ut + 2451545.0
+  )}
+  <br>JDE (J2000): ${astroTime.tt.toFixed(6)}`;
 }
 
 function updateTimeFromUT() {
@@ -119,7 +124,10 @@ function updateTimeFromUT() {
   tt.value = astroTime.tt + 2451545.0;
   ts.value = +dateNew;
   tss.value = Math.floor(+dateNew / 1000);
-  jde.innerHTML = `JDE (J2000): ${astroTime.tt.toFixed(6)}`;
+  jde.innerHTML = `Julian Calendar(UTC): ${jd2JulianCalendar(
+    astroTime.ut + 2451545.0
+  )}
+  <br>JDE (J2000): ${astroTime.tt.toFixed(6)}`;
 }
 
 function updateTimeFromTS() {
@@ -135,7 +143,10 @@ function updateTimeFromTS() {
   ut.value = astroTime.ut + 2451545.0;
   tt.value = astroTime.tt + 2451545.0;
   tss.value = Math.floor(ts.value / 1000);
-  jde.innerHTML = `JDE (J2000): ${astroTime.tt.toFixed(6)}`;
+  jde.innerHTML = `Julian Calendar(UTC): ${jd2JulianCalendar(
+    astroTime.ut + 2451545.0
+  )}
+  <br>JDE (J2000): ${astroTime.tt.toFixed(6)}`;
 }
 function updateTimeFromTSSec() {
   const dateNew = new Date(Number(tss.value) * 1000);
@@ -150,7 +161,33 @@ function updateTimeFromTSSec() {
   ut.value = astroTime.ut + 2451545.0;
   tt.value = astroTime.tt + 2451545.0;
   ts.value = Number(tss.value) * 1000;
+  jde.innerHTML = `Julian Calendar(UTC): ${jd2JulianCalendar(
+    astroTime.ut + 2451545.0
+  )}
+  <br>JDE (J2000): ${astroTime.tt.toFixed(6)}`;
+}
+//method from swisseph: swe_revjul
+function jd2JulianCalendar(jd, includeHour = true) {
+  const u0 = jd + 32082.5;
+  const u2 = Math.floor(u0 + 123.0);
+  const u3 = Math.floor((u2 - 122.2) / 365.25);
+  const u4 = Math.floor((u2 - Math.floor(365.25 * u3)) / 30.6001);
+  let month = u4 - 1;
+  if (month > 12) month -= 12;
+  const day = u2 - Math.floor(365.25 * u3) - Math.floor(30.6001 * u4);
+  const year = u3 + Math.floor((u4 - 2.0) / 12.0) - 4800;
+  if (includeHour) {
+    const hour = (jd - Math.floor(jd + 0.5) + 0.5) * 24.0;
+    const hour_int = Math.floor(hour);
+    const minute = Math.floor((hour % 1) * 60);
+    const second = ((hour * 60) % 1) * 60;
+    return `${year}-${month}-${day} ${hour_int}:${minute}:${Math.floor(
+      second
+    )}`;
+  }
+  return `${year}-${month}-${day}`;
 }
+
 //logic about the date and time input
 const nextThreshold = [1680, 2, 4, 3, 6, 6];
 const maxValue = [16800, 12, 31, 24, 59, 59];