Mr. Klepper developed the Moon Clock several years ago when a Texas Parks and Wildlife Department biologist mentioned that deer trappers with the state agency check the moon phases before waiting for the animals to congregate under drop nets.

The different phases of the moon influence the times of day deer and other creatures are most active. By manning the baited nets only during major activity periods, the trappers were able to save themselves time and trouble.

The Moon Clock is a quick reference for hours of two major movements during any given 24-hour period.

The Moon Clock predicts these activity periods for any date in any year in the future if the hunter can obtain the dates of moon phases that far in advance.

The lines on the clock indicate the approximate middle of each period. Each lasts from 2 to 3 hours.

To use the clock:

• Check the calendar or some other source for dates of the phases of the moon during hunting season. For a quick reference, see the U.S. Naval Observatory's Moon Phase page at http://tycho.usno.navy.mil/vphase.html.
• Determine if the day you plan to hunt falls exactly on a date when a certain phase occurs or between two phases.
• Locate the times on the clock the two major activity periods will occur on your hunting day.

Activity periods and moon phases rotate clockwise. The last quarter follows the full moon, the new moon the last quarter, the first quarter the new moon and the full moon the first quarter.

Following are some examples of the major activity periods during the four phases:

• On the precise date of a full moon, major activity periods will straddle noon and midnight, from approximately 10:30 a.m. to 1:30 p.m. and again from 10:30 p.m. to 1:30 a.m.
  
  
• On the precise date of the last quarter, the activity periods will straddle 3 a.m. and 3 p.m., from approximately 1:30 to 4:30 a.m. and 1:30 to 4:30 p.m.
  
  
• On the precise date of the new moon, the activity periods will straddle 6 a.m. and 6 p.m., from approximately 4:30 to 7:30 a.m. and 4:30 to 7:30 p.m.
  
  
• On the precise date of the first quarter, the activity periods will straddle 9 a.m. and 9 p.m., from approximately 7:30 to 10:30 a.m. and 7:30 to 10:30 p.m.

If the date you plan to hunt falls between the precise dates of two phases, simply estimate when the activity periods will take place. As an example, let's say the first quarter falls on the 18th, the full moon on the 25th, and you plan to hunt on the 21st and 22nd (dates in between the two phases). Check the times between these two phases on the clock. Note that a major activity period should occur during the late morning, from around 9 a.m. to noon, on the 21st and 22nd.

The corresponding major activity period will be between 9 p.m. and midnight, when deer hunting is illegal.

Since deer usually are active around dawn and dusk each day, your most productive hunting on either the 21st or 22nd should be from daylight until at least noon. If you are going back to the camp to rest, do it in the early afternoon. You can be out in the field again for what probably will be a short activity period around sundown.