The Solunar Theory
In 1926 John Alden Knight* postulated some folk lore he picked up in Florida and proceeded to attempt a refinement, giving it the name Solunar (Sol for sun and Lunar for moon).
Knight compiled a list of 33 factors which influence or control day-to-day behavior of fresh and salt-water fish. Everything was taken into account that could possibly have any bearing on the matter.
One by one the factors were examined and rejected. Three of them, however, merited further examination. They were sun, moon and tides. Surely the sun could have no effect since its cycle was the same day after day, whereas the observed activity periods of fish were apt to be present at most any time of the day or night.
The moon had already been weighed and found wanting. Tides? Surely there could be no tidal movement in a trout stream. But the fact remained, however, that the tides had always guided salt-water fishermen to good fishing. Could it be that the prompting stimulus lay in the influence of the sun and moon which cause the ocean tides, rather than the actual tidal stages or flow?
When the original research was being done only the approximate time of moon up - moon down were considered. Gradually, it became evident that there were also intermediate periods of activity that occurred midway between the two major periods. Thus the more evident periods were called major periods and the two intermediate periods, shorter in length, were called minor periods.
One convincing experiment was when Dr. Frank A. Brown, a biologist at Northwestern University, had some live oysters flown to his lab near Chicago. Oysters open their shells with each high tide, and Dr. Brown wanted to see if this was due to the change in ocean levels or to a force from the moon itself.
He put them in water and removed them from all sunlight. For the first week they continued to open their shells with the high tides from their ocean home. But by the second week, they had adjusted their shell-openings to when the moon was directly overhead or underfoot in Chicago.
Knight first published his tables in 1936. Then, and today, one must calculate the precise times from each table taking into account the geographic location (east or west) of a base point (Time Zone), and adjusted for Daylight Savings Time when appropriate. Knight's tables are then rounded to the nearest 10 minutes.
An example of the deviation in time in a particular state would be Texas. The time difference from El Paso on the western border and Hemphill on the eastern border is 51 minutes (Hemphill is 51 minutes earlier than El Paso).
PROVING THE THEORY
To substantiate the theory, insofar as fish are concerned, John Alden Knight attempted a systematic inquiry to acquire complete details surrounding the capture of record catches. Both individual large fish ... and large numbers. He examined approximately 200 of these catches. Over 90 percent were made during the dark of the moon (new moon) when the effects of of the periods appear to be greatest, and, more important, they were made during the actual times of the Solunar Periods.
Initially, only the behavior of fish was considered. During 1935 to 1939 Knight made extensive studies of game birds and animals. As had been suspected, these also responded to the prompting stimulus of the periods.
It is now known that the sun and moon are the two major sources of the astral energies that daily bombard the Earth and all her life forms. The closer they are to you at any given moment, the stronger the influence. The day of a new or full moon will provide the strongest influence in each month.
June always has more combined sun-moon influence than any other month. During a full moon, the sun and moon are nearly opposite each other and very few minutes pass without one or the other being in our sky. During a new moon, both bodies are in near-perfect rhythm traveling the skies together with their forces combined. Because of the interaction between the many lunar and solar cycles, no two days, months or years are identical.
When a period falls within 30 minutes to an hour of sunrise or sunset you can anticipate great action! When you have a moonrise or moonset during that period the action will be even greater. And, finally, when the above times occur during a new or full moon, you can expect the best action of the season!
LENGTH OF PERIODS
Every fisherman knows that fish do not feed all the time. He knows, also, that for some reason fish often go on the feed and take most any offering, be it live bait or artificial. This sort of thing happens, according to John Alden Knight (the originator of the theory) during a period. To be sure, fish usually feed actively at sunrise and sunset, but generally, the real fishing of the day is at the odd hour feeding periods. If the weather and feeding conditions are favorable the fish will be active for one to two hours.
WATCH THE BAROMETER
Intensity of activity also varies from day to day, according to conditions in general. If the barometer happens to be steady or rising, if the temperature is favorable (15 degrees higher than water temp) then long and active response to a period can be expected.
WATCH THE MOON
Another thing to remember in dealing with the periods is that solunar influence will vary in intensity according to the position of the moon. The times of new moon (the dark of the moon), and there is no moon in the sky, is the time of maximum intensity.
Ocean tides reflect this intensity in their magnitude. This maximum will last about three days, and wildlife respond with maximum activity. Thereafter the degree of intensity tapers off until it is at its minimum during the third quarter phase of the moon. Salt-water anglers argue that tides have a greater influence on fish feeding habits than the moon itself. It must be understood that the tides are governed by the phases and transit of the moon. Certain marine phenomena occur with precise regularity during the lunar month and solar/lunar cycle.
Research has shown that a natural day for fish and many other animal species differ from our own. Their biological clock appears to coincide with lunar time, which is the time that it takes for the moon to reappear at a given point during one complete rotation of the earth (an average of 24 hours and 53 minutes). This is called a Tidal Day and explains why the ocean tides are about an hour later each day - and why most fish, fresh water species included, will feed up to an hour later (in relation to our solar clock) each day.
CALCULATING THE TIMES
The key to accurate Solunar Times is the ability to chart the relative solar and lunar positions with respect to a particular location. The major periods coincide with the upper and lower meridian passage of the resultant gravitational (tidal) force.
The minor periods occur when these forces are rising or setting on either horizon, i.e., the right ascension of the resultant force and the local sidereal time vary by 90 or 270 degrees. The major periods occur when these forces are at 0 and 180 degrees apart.
AREA COVERED BY THE TIMES
The times produced are known as equilibrium tide times, i.e., the times of low and high tides if the Earth were completely covered by water. Our program calculates the solar and lunar positions with an accuracy of .25 degrees allowing accuracy to be within 1 minute in time. The times will change one minute for each 12 miles east or west of the base point.
There is one day each month (near the last quarter of the moon) on which there is no moonrise. This is normal and occurs because the moons average period between two rises and sets is approximately 24 hours and 50 minutes. Thus there will always be a day on which a moonrise (and a Solunar Time) will not fit. Note also that moonrise can occur at any time during the day or night.
The quantities required for computing the times are elliptic longitudes of the Sun and Moon, the right ascension (RA) of the moon, and the local sidereal time of the observer's position.
BEST FISHING DAYS
For those fishermen who enjoy fishing at sunrise and sunset, here are the absolute best dates to be on the water at your favorite spot. These are the Major or Minor Periods that fall near the times of Sunrise or Sunset during a Full or New Moon.
It has been documented that when this condition exists fish will bite on anything they see or smell. Limits are almost guaranteed provided there are fish in the vicinity.
Its no secret that fish and game tend to feed during dawn and dusk (sunrise and sunset). What amplifies the activity is the effect of a moonrise or moonset plus the specific monthly periods of New (dark) and Full (light) Moons.
When the times coincide with a moon-rise or a moon-set the action can be spectacular. Finally, a change in the local weather coinciding with the periods will further enhance the activity.
For an interesting article on this subject, visit The Real Scoop on using the theory to your advantage.
WATCH THE WEATHER
For best results the tables must be used intelligently. Every day will not show a clear-cut reaction to a period. In the case of fish, barometric fluctuations, particularly when the trend is down, often ruin fishing. All wildlife knows what to expect of the weather, and any bird, animal or fish can sense the approach of a storm. Cold fronts moving through drive all fish deeper and render them inactive.
Adverse temperature, abnormal water conditions, all sorts of things will offset the effects of periods. However, every sportsman knows that it is beyond all reason to expect good fishing or hunting every day. The theory will point the way to the best in sport that each day has to offer, but in no sense is it a guarantee.
It goes without saying that if there are no fish or game present, you will not be successful. Plan your days on the water or in the field so that you are where the game is most likely to be during the periods.
We hope that we have been able to improve your understanding of the theory - and how you can use it to improve your angling success. But always remember ... the best time to go fishin ... is whenever you can and always practice catch and release.