...

mcc/mcc_defaults.h

@@ -22,19 +22,37 @@ typedef std::chrono::system_clock::time_point MccTimePoint;
 
 struct MccJulianDay {
     static constexpr double MJD0 = 2400000.5;
-    double mjd{51544.5};  // J2000.0
+
+    MccJulianDay() = default;
+
+    MccJulianDay(double jd) : mjd(jd - MJD0) {}
 
     constexpr operator double() const
     {
         return MccJulianDay::MJD0 + mjd;
     }
 
+    MccJulianDay& operator=(double jd)
+    {
+        mjd = jd - MJD0;
+
+        return *this;
+    }
+
+    double MJD() const
+    {
+        return mjd;
+    }
+
     constexpr auto operator<=>(const MccJulianDay&) const = default;
 
     constexpr auto operator<=>(double v) const
     {
         return v <=> (MccJulianDay::MJD0 + mjd);
     };
+
+protected:
+    double mjd{51544.5};  // J2000.0
 };