This class represents a Modified Julian Date, which is defined as the Julian date minus 2,400,000.5.
To create an MJD instance, use this calling sequence:
m may be either a
float or an
int. If you would
like to carry extra precision, you can pass the integral
m and the fraction as
f. The integral and fractional parts are
carried separately inside the object, so that finding
the difference between two
gives you a full 15 digits after the decimal.