Tithi – Lunar Day

The Tithis are the 30 divisions of the synodic cycle¹ between the Sun and Moon, or put another way, the 30 lunar days between one New Moon and the next. The actual length of the Solar-Lunar synodic cycle is about 29.5 days. Therefore, we would think each Tithi is slightly shorter than an actual twenty-four-hour day. However, due to the varying speed of the Moon, the tithis are irregular in length of time, just like the Nakshatras are.

Each tithi is measured by a 12° movement of the Moon away from the Sun. This is because on average the Moon moves 13° a day while the Sun moves 1°. This creates an average daily separation of 12°. However, the lunar day represented by the tithi may be shorter or longer than an actual day.

The tithi is determined by the tithi in place at sunrise, the start of the day. It does not matter if you are electing an event for the afternoon and the tithi changed between sunrise and the time of the Muhurta. The tithi at sunrise is the only tithi of the day that matters. Since the sun rises at different times in different locations, the tithi in place at sunrise varies by location and therefore the Panchanga must be consulted for the specific location where the action is taking place.

Since the tithi in place at sunrise is the only one that matters and since the tithi can be longer than one actual day when the Moon is slow, it is possible for the same tithi to occur at sunrise two days in a row. This is called vriddha tithi, or increased tithi. These should be avoided because the Moon is slow.

Similarly, when the Moon is fast, it is possible for two tithis to occur in one day. Now, most of the time two tithis do occur in the day because the tithi changes sometime in the midst of the day or night. But usually the immediately following tithi is in place at sunrise on the following day. However, if the tithi in place at sunrise is nearly finished and the Moon is fast, then the next tithi can complete before the next sunrise. This skips a tithi in the Panchanga because a third tithi will be in place on the next sunrise. When this happens, it is called kshaya tithi, or decreasing tithi.

The Tithis & Prakriti

The Tithi of the Moon through the waxing and waning cycle shows the formation and withdraw of the five elements, the five organs of perception and the five organs of action through the manifestation of Prakriti. The tithis are numbered from 1 – 30 beginning on the day after the New Moon. The first 15 tithis occur during the waxing cycle of the Moon, the bright half called Shukla Paksha, when it is increasing in light and is less than 180° ahead of the Sun. The second 15 tithis occur during the waning cycle of the Moon, the dark half called Krishna Paksha, when it is decreasing in light and is greater than 180° ahead of the Sun.

The first five tithis of Shukla Paksha represent the formation of the five Maha Bhutas and relate to the earth element. They are good for setting things in motion, establishing foundations and starting new ventures. The second five tithis of Shukla Paksha represent the formation of the five organs of perception and relate to the water element. They are good for developing action and sustaining accomplishment. The last five tithis of Shukla Paksha represent the formation of the organs of action and relate to the fire element. They are good for developing knowledge, and undertaking creative or spiritual ventures. Day 15 is the Full Moon.

The first five tithis of Krishna Paksha represent the withdrawal of the organs of action and relate to the air element. They are good for evaluation and bringing things to completion. The second five tithis of Krishna Paksha represent the withdrawal of the organs of perception and relate to the ether element. They are good for contraction and consolidation. The last five tithis of Krishna Paksha represent the withdrawal of the five Maha Bhutas and have no elemental correspondence. They are good for internalization, revision, reorganization and reform. Day 30 is the New Moon.

The Moon represents our manas mind. The Sun represents vitality. The Moon reflects the light of the Sun. Mental energy and prana are lowest at the dark of the New Moon and highest at the Full Moon. As the Moon waxes our mental and vital energies increase. As the Moon wanes they decrease. Depending on our level of control of our senses the New Moon can be a time of feeling alone and vulnerable or a time of negating the mind and merging into the Atman. Similarly, the Full Moon can be a time of excess emotion or self-indulgence or a time of experiencing the bliss of spiritual realization and sense of Being.

Additionally, the tithis can be grouped in to five different categories with yet another elemental association. The numbers in the following table are to be taken as days 1 – 15 in both the Shukla & Krishna Paksha. Where day 1 also corresponds to day 16 and day 15 also corresponds to day 30.

Table: The Five Groups of Tithis

Favorable & Unfavorable Actions for Each Tithi
Tithis 1, 15, 16 & 30 representing the New and Full Moon and the day after each have their own individual meanings. Tithis 2-14 in the Shukla Paksha have the same meaning as tithis 17-29 in the Krishna Paksha. In regard to outward actions, the bright half brings out the more positive qualities while the dark half brings out the negative qualities. Yet the dark half is good for renunciation and withdrawal.

In general, the waxing tithis are more favorable than the waning tithis. The exception is the day after the New and Full Moon. The day after the New Moon begins the Shukla Paksha, however the Moon is still within 12° of the Sun, combust and therefore unfavorable. The day after the Full Moon begins Krishna Paksha, but is still very bright and therefore favorable.

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¹A synodic cycle can occur between any two bodies. It begins when they conjoin and ends at their next conjunction which begins the next synodic cycle.