Calculating Losar

Losar falls on Februrary 14th, 2010 this year on the Gregorian calendar.

Losar is the Tibetan word for "new year." Lo means "year, age"; sar means "new, fresh". Losar is the most important holiday in Tibet. Despite its importance, few Westerners
understand how its date is calculated. This post will give a brief overview of the Tibetan calendar and how the date for Losar is arrived at.

The Tibetan calendar is luni-solar. That is to say, it is a calendar that indicates both the Moon phase and the position of the Sun. The Tibetan calendar also incorporates Chinese and Vedic elements. This post will deal with the Chinese elements.

Like many of the oldest calendar systems, the first of each month coincides with the New Moon on the Tibetan and Chinese calendars. Various important religious observances are then celebrated a set number of days from this occurrence (for example, Guru Rinpoche Day is always the tenth day of the lunar month).

The Chinese and Tibetan calendars also use solar calculations in order to keep the calendar in sync with the seasons. This means that the Tibetans and the Chinese strive to have the New Year occur near a chosen point on the elliptic (the apparent path of the sun through the sky, a circle labeled from 0° to 360°) and the first day of the New Year also coinciding with the New Moon.

Various strategies are used to make sure the new moon and the first of the month occur on the same day. The solar year (365.24 days) is eleven days longer than the  lunar year (29.5 days per lunar cycle x 12 months = 354 days in a lunar year). Therefore, on the Tibetan calendar, days are added (“extra days” tsi lhag-pa) or occasionally subtracted (“skip-days” tsi chad-pa) from a given month so that the first of the month always coincides with the New Moon. This is the reason why one will occasionally see on a Tibetan calendar the days numbered 12, 12, 13 and so on. Approximately every 30 months an additional “leap month” will also be inserted into the calendar. The repeated day or month is generally considered inauspicious and therefore important activities should not start at these times.

Before considering how Losar is calculated, first we need to look at the Chinese agricultural calendar. Most people are aware of the Tibetan and Chinese zodiacs, where each year
is said to be under the influence of one of the five elements and one of twelve animal signs. In addition, in China, each individual year is also divided into 24 jiéqì. The term jiéqì is usually translated as "solar terms" (lit. Nodes of Weather). The beginning of each jiéqì is the point on the ecliptic where the Sun reaches one of twenty-four equally spaced intervals positioned every fifteen degrees (by convention, the Spring Equinox is considered 0° on the elliptic).

Ecliptic                    Translation         Approx.Gregorian date
315°  lichun            start of Spring               February 4
330°  yǔshuǐ           rain water                      February 19
345°  qǐzh               awakening of insects    March 5
0°      chunfen         spring equinox              March 21
15°    qīngmíng       bright and clear            April 5
30°    gǔyǔ              grain rains                    April 20
45°    lìxià               start of summer            May 6
60°    xiǎomǎn        grain full (plump)          May 21
75°    mángzhòng   beard of grain              June 6
90°    xiàzhì             summer extreme         June 21
105°  xiǎoshǔ         minor heat                    July 7
120°  dàshǔ            major heat                    July 23
135°  lìqiū               limit of heat                   August 7
150°  chùshǔ          white dew                     August 23
165°  báilù              central divide of          September 8
                               autumn
180°  qiūfēn            cold dew                     September 21
195°  hánlù             decent of frost              October 8
210°  shuāngjiàng   start of winter              October 23
225°  lìdōng             minor snow                 November 7
240°  xiǎoxuě          major snow                 November 22
255°  dàxuě            winter extreme           December 7
270°  dōngzhì         winter solstice            December 21
285°  xiǎohán         minor cold                     January 6
300°  dàhán            major cold                    January 20

http://en.wikipedia.org/wiki/Chinese_calendar

In order to keep the lunar monthly calendar in sync with the position of the sun, Chinese New Year is calculated from the second New Moon following the jiéqì of dōngzhì (Winter
Solstice 270°)

While researching the origin of Losar, I noticed that many authors stated that Losar is the first New Moon after February 4th. So this got me thinking, what’s so special about February 4th? After pondering this for a while I checked to see how February 4th corresponds with the solar
terms. Lo and behold, lichun falls on or about February 4th. So Losar is the first New Moon after the Sun enters 315° (incidentally 315° = 15° Aquarius on the Western zodiac).

Various explanations are given as to why this particular point in the year was chosen to mark the New Year. One of the more widely repeated explanations is that it commemorates the anniversary of the victory of the Mongolian army, under Chingas Khan, over the Chinese
Song dynasty and the beginning of the Yuan dynasty in 1215 ce. The Mongol led Yuan dynasty became an important patron of Tibetan Buddhism with Sakyapa lamas acting as secular advisors and spiritual preceptors to the imperial court in Beijing. So it may be that the Tibetans chose this date to mark the New Year as a way of honoring their patrons. To this day, the majority of Mongolians practice Vajrayanna Buddhism.

To calculate Losar for yourself go to: http://www.khaldea.com/ephemcenter.shtml and look to see when the Sun reaches 315° (15° Aquarius ) for any given year. Next, go to:
http://www.timeanddate.com/calendar/moonphases.html and determine the date for the first New Moon after the Sun has entered 315° for a given year. Finally, for a list of Losar dates over the last century, go to: http://www.olnagazur.org/tsagan.html

You will see that the dates for the first new moon after the Sun enters 315° and Losar agree, ALMOST. So why the discrepancy?

The Dalai Lama's astrologers are calculating the date of the New Moon from their location in the Eastern Hemisphere. Frequently the day of the New Moon at that longitude will differ by up to a day compared to persons spotting the New Moon in the Western Hemisphere (this is why it is important to enter the location you are observing from in the moon calculator web site cited above). BUT, you will also see various Tibetan calendars that mark Losar as one day, and another Tibetan calendar states that Losar is the day after. So why is this?

Besides New Moon discrepancy, further complicating the matter is that there are two major calendars in use in Tibet. These are called the P'hukluk and Tsurluk calendars. The Gelupgas, Sakypas, Ningmapas and most of the Kagupa sects use the P'hukluk calendar. The Karma Kagu sect, on the other hand, uses the Tsurluk calendar. For a brief description of the difference between these two, see: http://www.nitartha.org/calendar_traditions.html

I have no real insight into why the P'hukluk and Tsurluk calendars differ. My impression is that the difference arises from somewhat different interpretations of the Kalacharkra Sutra, but that is beyond me.

If you bought a Tibetan calendar this year published by Nirantha you’ll see that they use the Tsurluk calendar to calculate various important holidays. If you bought a calendar published by the Foundation for the Preservation of the Mahayana Tradition you’ll see that they used the P’hukluk calendar to calculate holidays.

So, as they say in Tibet, "A different lama, a different teaching", and maybe we can add, "and a different date for Losar". Anyways, may Losar bring you happiness and the causes of happiness, and may you be free from suffering and the causes of suffering.

For more information on Tibetan astrology and the Tibetan calendar see:
“Tibetan Astro Science”, by Jampa Kalsang, published by Tibet Domani, 2000, Rome
“Eastern Systems for Western Astrologers: An Anthology”, ed. By Thomas Moore, Ch. 4, “Tibetan Astrology” by Michael Erlwine, published by Weiser, 1997, York Beach Maine
http://earlytibet.com/2008/11/28/the-golden-turtle/
"A modern attempt to reform the Tibetan calendar" 
www.math.uu.se/~svante/papers/calendars/tibet.pdf