SLA_CLDJ - Calendar to MJD   

ACTION:

Gregorian Calendar to Modified Julian Date.

CALL:

CALL sla_CLDJ (IY, IM, ID, DJM, J)

GIVEN:

IY,IM,ID year, month, day in Gregorian calendar

RETURNED:

$$0^{\rm h}$$ DJM

J I status: 0 = OK 1 = bad year 2 = bad month 3 = bad day

NOTES:

1.

When an invalid year or month is supplied (status J = 1 or 2) the MJD is not computed. When an invalid day is supplied (status J = 3) the MJD is computed.

2.

The year must be -4699 (i.e. 4700BC) or later. For year nBC use IY = -(n-1).

3.

An alternative to the present routine is sla_CALDJ, which accepts a year with the century missing.

REFERENCE:

The algorithm is derived from that of Hatcher, Q.Jl.R.astr.Soc. (1984) 25, 53-55.