PHP juliantojd() Function

The PHP juliantojd() function converts a Julian Calendar date to Julian Day Count. The valid range for Julian Calendar for this function is 4713 B.C. to 9999 A.D.

Although this function can handle dates all the way back to 4713 B.C., such use may not be meaningful. The calendar was created in 46 B.C., and it did not stabilize until at least 8 A.D. Also, the beginning of a year varied from one culture to another - not all accepted January as the first month.

Syntax

juliantojd(month, day, year)

Parameters

Return Value

Returns the Julian Day count for the given Julian Calendar date. Dates outside the valid range return 0.

Exceptions

NA.

Example:

The example below shows the usage of juliantojd() function.

<?php
//converting a Julian Calendar Date
//to Julian integer 
$jd = juliantojd(10, 2, 2015);
  
//displaying the Julian day integer 
echo "The Julian day integer is: $jd \n";
  
//converting the Julian day integer 
//to Julian Calendar Date
$date = jdtojulian($jd);
  
//displaying the Julian Calendar Date
echo "The Julian Calendar Date is: $date \n"; 
?>

The output of the above code will be:

The Julian day integer is: 2457311 
The Julian Calendar Date is: 10/2/2015 

Example: Overflow behavior

Consider one more example to see the overflow behavior of this function.

<?php
//converting an invalid Julian Calendar 
//date to Julian integer 
$jd = juliantojd(15, 2, 2018);
  
//prints 0 as month is out of range 
echo "The Julian day integer is: $jd \n";
  
//converting the Julian day integer 
//to Julian Calendar Date
$date = jdtojulian($jd);
  
//prints 0/0/0 as Julian Calendar 
//month is out of range
echo "The Julian Calendar Date is: $date \n"; 
?>

The output of the above code will be:

The Julian day integer is: 0 
The Julian Calendar Date is: 0/0/0