If the hour and minute of birth is unknown then enter 12:00 (P)m or make an educated guess. The Personal Day section maps out a 24 hour period starting and ending at the
 Birth Hour. The Peak Hour approximates the time when the Personal Day # forces are especially active but is meant as a guideline only. Narrowing it down to either morning or evening should suffice in most cases. (The exact time of birth is recorded on  the Subject's Birth Certificate.)