Hindu Calendar

Hindu Lunar Calendar Usage Tithi (Lunar Phase) of the Moon The first element of the Hindu panchang is the tithi or lunar phase. This is perhaps the single most important element of the panchang. It is the building block for the lunar month. Simply stated a tithi is a measurement of 12 degrees of longitudinal separation between the sun and the moon. Another way to put it is to say that a tithi is the daily phase of the moon.

For example, at new moon (amavasya) the sun and the moon are in conjuction by zero degrees. We can say they overlap. As they begin to separate the first tithi or the phase of the moon begins when the sun and the moon have separated by 0 to 12 degrees. The moon is now a tiny almost imperceptable sliver. The second tithi or the moon phase begins when they are separated by 12 to 24 degrees. The sliver shine is slightly larger. The third tithi begins when they have separated by 24 to 36 degrees.

And so it goes until the sun and moon have separated by 180 degrees. This moon phase is called full moon, purnima. These first 15 tithis or phases of the moon make up the waxing phases of the moon which in Sanskrit this is called the sukla-paksa. This is the bright side of the lunar month.
After purnima, full moon, the tithi begins again counting from one as the longitudanal separation between the sun and the moon decreases back to zero. This is called the waning phase of the moon or in Sanskrit, the krsna-paksa or dark side of the lunar month.

The different moon phase can last between 15 to 26 hours due to the changing speed of the earth and moon in their obits. On average a moon phase can lasts for only 0.95 of a solar day. When this occurs a break in the numerical ordering of the days takes place. These factors cause a lot of confusion between the lunar  calendar and the modern solar calendar.
In addition the 8th and 14th tithis, amavasya, as well as the 1st tithi of the sukla-paksa are generally considered inuaspicious, sometimes referred to as negative energy or stressful combination.

The Sun is the centre of our solar system, and by far the dominant object in it. As well as providing the light and heat which power all life on Earth, it is by far the most massive object in the solar system: more than 300,000 times heavier than the Earth, and over 700 times heavier than all the planets put together. This huge mass acts as the anchor for the whole system: all of the other objects in the solar system -- planets, asteroids, moons, etc. -- are in orbit around the Sun, either directly, or indirectly as moons of other objects.

Our Moon is fairly unremarkable, except for its size; it is one of the larger moons in the solar system. The main reason it looks so big to us, though, is simply that it is very close; the Moon is just 384 thousand km away. By comparison, the Sun is 150 million km away.

Various cycles mesh together to produce the same set of circumstances -- and hence a similar eclipse -- every 18 years and 10 or 11 and a third days. (Whether it's 10 or 11 days depends on how many of the 18 years are leap years). Amazingly enough, this period was actually discovered 2,500 years ago, by Babylonian astronomers; it's called the Saros, meaning "repetition". You can, if you like, read more about the lunar months, and the cycles behind the Saros.

The Earth's umbra is ~1.4 Million km long: About 3.7x the mean Earth-Moon distance. Umbra's width is 9000 km at the distance of the Moon, or ~2.6x the Moon's diameter. The Earth's umbra is not totally dark because of light scattered by the Earth's transparent atmosphere. This gives the fully eclipsed Moon a slightly ruddy appearance (think about how the Sun looks reddish at sunset or sunrise)


The Moon's umbra is only 380,000 km long: Just long enough for the tip to touch the Earth. But not large enough to cover the entire Earth. Solar Eclipses can be seen only where the shadow passes overhead.
In ancient times, priests and astrologers discovered how to predict eclipses, having realised their significance. Using observation and mathematics, they prepared reliable tables utilising their knowledge of the movement of the Moon's Nodes that have hardly been surpassed for accuracy until the recent advent of the computer. The Moon's Nodes mark the points where the path of the Moon's orbit around the Earth crosses the path of the ecliptic (the apparent path of the Sun and planets around the Earth) as viewed from the surface of the Earth. An eclipse takes place when either a New Moon (producing a Solar Eclipse) or a Full Moon (producing a Lunar Eclipse) occurs close to the either of the Nodes.

The eclipse of the Sun has traditionally been viewed with dread over the ages, as the great giver of life seems inexplicably to disappear from the sky. Birds prepare for bed; the sky darkens in the middle of the day. It seems as though something dreadful is about to happen. Over the years, experience has shown us that old things come to an end (or are overthrown!) under a solar eclipse and a new beginning can be made. The effect on the world has been seen to be generally felt for some six months, until the next eclipse then restructures the cosmic energies.

As the whole Earth-Moon system orbits around the Sun every year, the two nodes will find themselves aligned with the Earth and Sun (one in between, and one "behind" the Earth) twice a year; this means that there are two times each year when we can get an eclipse. Because the node doesn't have to be exactly lined up to cause an eclipse, there is actually a period of 37 days during which an eclipse can occur. These times -- when one of the Moon's nodes is approximately in line between the Earth and Sun, so there is the possibility of an eclipse -- are called eclipse seasons.

As the Moon goes round the Earth, if it passes through either node during an eclipse season, an eclipse will occur; a solar eclipse if the new Moon passes the node between the Earth and Sun, or a lunar eclipse if the Full Moon passes the other node. Furthermore, if the Moon is (more or less) exactly at that node at the middle of the eclipse season, the eclipse will be total (or maybe annular, for a solar eclipse) as seen from some part of the Earth.

Total Solar Eclipses are localized and short: The Moon's umbral shadow is at most 267 km across on the Earth. Totality lasts at most about 7.5 minutes, with the shadow sweeping rapidly west-to-east. Only observers in the umbra see a total solar eclipse. Observers in the penumbra see a partial solar eclipse. Everyone else sees nothing. Solar Eclipses occur when the Earth passes through the shadow of the Moon. Solar Eclipses only occur during New Moon, when the Moon is between the Earth and the Sun. Total Solar Eclipse: The observer is inside the Moon's umbra.


One can be guided by astronomical calculations to help one to know when and where to search for the crescent moon. This has brought to light that many countries have hitherto been in error in establishing the beginning of the new month, Saudi Arabia included. Some have accepted they have been in error and are now revising their position on that count.

It is important that we do not follow blindly but we seek to understand and convince ourselves of the validity of methods employed. The modern era of internet access and electronic communication seeks to educate and unite Muslims like we never could before. Especially the Hadith states if it is cloudy then calculate for it, commands confirming the month with the calculations rather than the negation. Scientifically it does not matter whether we use the astronomical calculations for confirmation or negation.

They are precise and accurate anyway. No jurists have ever required such a sighting because the sighting was prescribed for certainty and not for the sake of sighting itself. Once that certainty is achieved by completing 29/30 days, Sighting is not even required and the new month is started. Everybody knows that the 1st phase of the new moon must be in the horizons by the 29 or 30th of Sha’aban month.

GMT is an arbitrary convention accepted by the international community to facilitate the timings and dates. On the other hand, Makkah, being the Qiblah point for the prayers for all the Muslims, enjoys a lot more significance than the GMT. Therefore, Muslims may take Makkah, Qiblah, as the Islamic centre to determine Islamic months for the purpose of making Islamic calendar.
1. The 1st Phase of Waxing Moon can be around 12 PM (GMT) To make a Universal Acceptable Worldwide Islamic Calendar

2. The new month can start when the 1st phase of the Moon starts before Sunset taking consideration of Mecca and stays in the horizon around the Sunset, even for a small amount of time. Time Zone as per longitude and latitude (2hrs 39mts)

Important Note: A Hilal will not be always seen by the dates calculated on the basis of the “Conjunction before 12:00 Noon GMT or the Conjunction date (by ending time of New Moon) with the moonset after the sunset in Makkah” but the presence of the 1st phase would have started for sure, which can be confirmed by next day as the day of the 2nd phase of the moon, refered to as Hilal Sighting

Looking at table of the Birth of New Moon and the end phase of New Moon, we can quickly find out from the data that for a Eclipse to happen, it would be at the End phase of the New Moon or Full Moon.
The 22 July 2009 the Sun Total Eclipse will last for 03 to 6 minutes in the morning 2.36 AM (Is this Safe to start Isamic new month?) The 1st Phase of Waxing New Moon is just a sign of timings. It has a beginning and a clear end while going around in its orbit around the earth.

The beginning point is the birth point and is the most certain point which can be forcaste months and years ahead of time with the help of accurate astronomical calculations. Therefore, there is nothing wrong in accepting the 1st phase of the New Waxing Moon as the starting of the new months.

Phases of Moon

The Full-moon phases correspond to 13th, 14th and 15th month, which are reported in the Hadith as Siyam Abyad or White Fasts. As the moon moves further, the shape changes, until we see the “reverse crescent” at Fajr. Then it disappears completely, typically for one or two days until it reappears as the Hilaal and the cycle repeats. The 1st lunar day or ends at around 12° of solar separation, and the 2nd lunar day begins. The only part of this, that might be confusing is that the 30th lunar day (348 to 360°) is considered the Birth of New Moon day and the 15th lunar day (168 to 180°) is considered the Birth of Full Moon day.
Moon Rise Times - New Moon Always Rises at Sunrise.
First Quarter of Moon Rises at Noon. The Full Moon Rises at Sunset.
The Last Quarter Moon Rises at Midnight.
MoonRise Takes Place about 48 Minutes Later Each day.
Lunar & Solar Eclipses in Ramadan
Type of Eclipse                                                    Type             Max. @    Region of Eclipse Visibility
Lunar in Mid Ramadan 1423    2002 Nov 20       Penumbral    1:02 UT    Americas, Europe & Africa
Solar at End Ramadan 1423    2002 Dec 4        Total        7:31 UT    Australia, Indnesia, S. Africa
Lunar in Mid Ramadan 1424    2003 Nov 9         Total       0:57 UT    Atlantic ocean
Solar at End Ramadan 1424    2003 Nov 23       Total        22:50 UT    W.Australia, Tip of South America
Lunar in Mid Ramadan 1445    2024 Mar 25       Penumbral    7:13 UT    N. & S. America only
Solar at End Ramadan 1445    2024 Apr 8        Total        18:17 UT    North America & Hawaii
Lunar in Mid Ramadan 1446    2025 Mar 14      Total         6:59 UT    Americas, Europe, Africa
Solar at End Ramadan 1446    2025 Mar 29     Partial        10:47 UT    West Europe, N.W.Africa

During  Solar or Lunar Eclipse, congregational prayers (2 Rak'aat) should be performed as done by the Prophet Muhammad (peace be upon him). According to Hadith, the Prophet performed 2 long Rak'aat in congregation when solar eclipse occured, and individual prayers are encouraged when lunar eclipse occurs.

The sighting of the lunar crescent within one day of New Moon is usually difficult. The crescent at this time is very thin, has a low surface brightness, and can easily be lost in the twilight. However, the Islamic calendar only lost its usefulness when Muslim theologians disconnected it from its astronomical, conceptual and methodological moorings, early in the 7th century.

The 1st lunar day or ends at around 12° of solar separation, and the 2nd lunar day begins. The only part of this, that might be confusing is that the 30th lunar day (348 to 360°) is considered the Birth of New Moon day and the 15th lunar day (168 to 180°) is considered the Birth of Full Moon day.

The Full-moon phases correspond to 13th, 14th and 15th month, which are reported in the Hadith as Siyam Abyad or White Fasts. As the moon moves further, the shape decrease (waning), until we see the “reverse crescent” at Fajr. Then it disappears completely, typically for one or two days until it reappears as the Hilaal and the cycle repeats.

In addition, the ecclesiastical Full Moon is not the astronomical. The Full Moon - - it is based on tables that do not take into account the full complexity of lunar motion. As a result, the date of an ecclesiastical Full Moon may differ from that of the true Full Moon. The ecclesiastical Full Moon is defined as the fourteenth day of a tabular lunation, where day 1 corresponds to the ecclesiastical New Moon.

The astronomical calculations especially about the birth of the new Moon and start of 1st phase of the waxing moon are more precise. They can be adopted as a means of affirming the new month to avoid the problems connected with actual sighting with the naked eyes.
The Week day start from midnight to midnight according to the western calendar to the count days of the week
The Week day called Vara starts from Sunrise to Sunrise for the Hindus to count the days of the week
The Islamic and the Jewish weekday starts from Sunset to Sunset to count the days of the week

Rahu and Ketu

Why do Hindus believe that the mythological demons Rahu and Ketu cause solar eclipses?
In Hindu astrology Rahu and Ketu are known as two invisible planets. They are enemies of the Sun and the Moon, who at certain times of the year (during conjunction or opposition) swallow the Sun or the Moon causing either a solar or a lunar eclipse. In Sanskrit this is known as grahanam or seizing. What perhaps sounds like a childish story is a powerful metaphor for what actually happens when an eclipse takes place.

Rahu and Ketu are the astronomical points in the sky respectively called the north and south lunar nodes.
Time the Moon takes to go from New to New (a Synodic Month) is different (due to the movement of the nodes) from the time it takes to travel from one node, around its orbit, and back to the same node again (a Draconic Month).

Rahu and Ketu are positions of mathematical calculations. Therefore, they are sometimes called invisible or shadow planets. Therefore, in the symbolic language of mythology, Rahu and Ketu are said to “swallow up” the Sun and the Moon. The ancient Hindu observers of the sky were aware of the cause of the solar and lunar eclipses and so described the process in the language of metaphor.

Solar eclipse only occurs at New Moon, when  the Moon passes between the Sun and Earth and the Moon's shadow sweeps across a portion of Earth's surface and an eclipse of the Sun is seen from that region. Solar eclipses are two to five per year, but the Area covered by totality is only a band of about 30 miles wide, length being that portion of the globe which is under the moon's shadow.

Lunar eclipse only occurs at End Phase of Full Moon, when the earth passes between the Sun and Moon and the Earth's shadow sweeps across a portion of Moon's surface and an eclipse of the Moon is seen. Thus, the closest time between solar and lunar eclipse is 2 weeks apart. Solar eclipse always occurs at the end of an lunar month. Lunar eclipse always occurs in the middle of an Solar month. During solar eclipse the sun is partially or totally blocked by the moon.


Eclipse Year - The Line of Nodes align with the Sun every 346.6 days. This is called the "Eclipse Year". But, it must be a Full or New Moon when the nodes line up to have an eclipse. This happens only very rarely. From a given location on the Earth you see - a Total Lunar Eclipse every 3 years (or so). - a Total Solar Eclipse every 360 years. Why are eclipses rare? If the Moon's orbit were exactly aligned with the Ecliptic, we would see A solar eclipse every New Moon.
A lunar eclipse every Full Moon But, this clearly does not happen.

Lunar Eclipses - Moon passes through the Earth's shadow - Total, Partial, & Penumbral lunar eclipses - Lunar Eclipses occur when the Moon passes through the shadow of the Earth. They only occur during Full Moon when the Earth is between the Moon and the Sun.

Solar Eclipses - Earth passes through the Moon's shadow - Total, Partial, & Annular solar eclipses - Total Lunar Eclipse: Entire Moon is within the Earth's umbra. Can spend up to 1h 40m in the umbra Whole show can last ~ 6 hours.

Umbra and Penumbra - Because the Sun appears as a disk ~1/2° across, Sun shadows are fuzzy rather than sharp. This means shadows cast by the Earth & Moon are two-part shadows: Umbra: Inner core of total darkness. The disc of the Sun is completely blocked. Penumbra: Outer, partial shadow - Sun's disc is only partly blocked.

Partial Solar Eclipse: The observer is inside the Moon's penumbra. Only see part of the Sun covered by the Moon. Annular Eclipse: The Moon is at or near apogee, and so is too small to cover the Sun. The Moon's umbra does not touch the Earth, so observer's in the shadow path see the Sun as a ring ("annulus").

Penumbral Eclipse: Moon misses the umbra completely, only passes through the penumbral shadow. Because the Moon can be completely immersed in the Earth's umbra during a total lunar eclipse, these eclipses can be seen from the entire night-time hemisphere. Why? The moon's orbit is tilted ~5° from the Ecliptic. Where the moon's orbit crosses the Ecliptic defines the "Line of Nodes" Eclipses only occur when the line of nodes and the Sun line up during Full Moon or New Moon.

Presentation Talks 2014

Religion Culture Diversity

Multi Faiths Calendar

27June Ramadan 2014
Astronomy eBook

Main Menu

SMSC Culture Education

Primary Education
Training Teacher eBook