PR_TIM2WEEK will convert a Yohkoh time into the corresponding week ID
and print a message on the screen. For example:
IDL> pr_tim2week ; Give the current week number
IDL> pr_tim2week,'15-nov-91'
IDL> pr_tim2week,'15-nov-91',/range
Setting the 
keyword will cause the routine to display the
first and last day of the week. Short weeks (the first or last
week of the year) are flagged with an asterisk. PR_TIM2WEEK
calls ANYTIM2WEEKID to make the conversion.