JDlist

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Description

Returns a list of the Julian Day Numbers corresponding to the first day of each month of the input interval. Useful for plotting.

Arguments and Return Values

Parameters: Numbers (scalars) specifying the starting year and month and the number of months (steps)

Return Value: A 2-by-n-by-1 float (single precision) array whose first column gives the rough "year fraction" (Y + (M-1)/12) and whose second column gives the corresponding Julian Day Numbers (JDN) for the first day of each of the n months, starting with the input year and month

Usage

Syntax: JDlist(year,month,n)

The Julian Date is a continuous count of days since noon UTC on January 1, 4713 BCE in the proleptic Julian calendar.

All inputs must be scalar integers.

For years before 1, use astronomical numbering, e.g. 4713 BCE = -4712. (There was no year 0.)

This function will guess the calendar mode (Julian or Gregorian), based on the latest input date. For (latest) input dates between October 15, 1582 and December 31, 1919 (when both calendar systems were in use), the function will print a warning about guessing the calendar mode. (Latest) dates before October 15, 1582 use the Julian calendar. (Latest) dates after that use the Gregorian (modern) calendar. This reflects the first changeover date. However, different countries changed at different times. See http://www.tondering.dk/claus/cal/node3.html

When JDlist() is entered without any arguments, it prints its description, as shown below.

Examples

dv> JDlist()

Returns the Julian Day Numbers corresponding to the first
 day of each month of the input interval
JDlist(year,month,n) returns 2-by-n-by-1 array of JDN of first
 day of month for n months, starting with input year/month
First column of output is rough "year fraction", Y + (M-1)/12
Second column of output is corresponding Julian Day Numbers
Useful for plotting
S.Marshall 08-25-2008

0
dv> # For the first day of each month of 2010:
dv> JDlist(2010, 1, 12)
2x12x1 array of float, bsq format [96 bytes]
2010.00000000000        2455198.00000000
2010.08337402344        2455229.00000000
2010.16662597656        2455257.00000000
2010.25000000000        2455288.00000000
2010.33337402344        2455318.00000000
2010.41662597656        2455349.00000000
2010.50000000000        2455379.00000000
2010.58337402344        2455410.00000000
2010.66662597656        2455441.00000000
2010.75000000000        2455471.00000000
2010.83337402344        2455502.00000000
2010.91662597656        2455532.00000000
dv> # For the fifteenth day of each month of 2010:
dv> JDlist(2010, 1, 12) + clone(1./24//14., 1, 12)
2x12x1 array of float, bsq format [96 bytes]
2010.04162597656        2455212.00000000
2010.12500000000        2455243.00000000
2010.20825195312        2455271.00000000
2010.29162597656        2455302.00000000
2010.37500000000        2455332.00000000
2010.45825195312        2455363.00000000
2010.54162597656        2455393.00000000
2010.62500000000        2455424.00000000
2010.70825195312        2455455.00000000
2010.79162597656        2455485.00000000
2010.87500000000        2455516.00000000
2010.95825195312        2455546.00000000

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Major Sub-Functions

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Recent Library Changes

Created On: 11-18-2009
Modified On: 05-07-2010

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