section_path: Days
section_name: Days
paragraph_text: Days
  
  There are three different types of days (zhag), the khyim zhag, the tshes zhag and the nyin zhag.
  
  The first two of these days are astronomical days. The time needed for the mean Sun to pass through one of the twelve traditional signs of the zodiac (the twelve khyim) is called khyim zla (solar month). One-thirtieth of one solar month (khyim zla) is one khyim zhag, which might be called a zodiacal day, because there is no equivalent name in Western terminology.
  
  The time needed by the Moon to elongate 12 degrees from the Sun and every 12 degrees thereafter is one tithi (tshes zhag, "lunar day"). The lengths of such lunar days vary considerably due to variations in the movements of the Moon and Sun.
  
  Thirty lunar days form one lunar or synodic month (tshes zla), the period from new moon to new moon. This is equal to the time needed for the Moon to elongate 360 degrees from the Sun (sun to sun). The natural day (nyin zhag) is defined by Tibetans as the period from dawn to dawn. Strictly speaking, the months appearing in a Tibetan almanac, called by us Tibetan calendar months, are not the same as lunar or synodic months (tshes zla), which can begin and end at any time of day. In Tibetan, there is no special term for a calendar month containing whole days. These calendar months are just called zla ba (month).
  
  A Tibetan calendar month normally starts with the week day or natural day (gza' or nyin zhag) in which the first tithi (tshes zhag) ends. A Tibetan calendar month normally ends with the week day or natural day (gza' or nyin zhag) in which the 30th tithi (tshes zhag) ends. In consequence, a Tibetan calendar month (zla ba) comprises 29 or 30 natural days. In the sequence of natural days or week days, there are no omitted days or days that occur twice. But since these days are also named by the term tshes together with a cardinal number, it happens that certain numbers or dates (the corresponding tithi) do not occur at all (chad) or appear twice (lhag). The tithi are counted from 1 to 30 and it can happen that a Monday with the lunar day number 1 (tshes gcig) is followed by a Tuesday with the moon day number 3 (tshes gsum). On the other hand, a Monday with the lunar day number 1 (tshes gcig) may be followed by a Tuesday with the lunar day number 1 (tshes gcig). In other words, it happens quite often that certain dates do not appear in the Tibetan almanac and certain dates occur twice. But there are no natural days or week days that occur twice or which are omitted.
  
  The days of the week (Tibetan: གཟའ, Wylie: gza') are named for astronomical objects.
  
  Nyima "Sun", Dawa "Moon" and Lhakpa "Mercury" are common personal names for people born on Sunday, Monday or Wednesday respectively.