Kendra is an important part of the horoscope in Hindu astrology. A Kendra (center) or a Kendra sthana (central place), representing a quadrant, is crucial in interpreting a horoscope. The zodiac is a broad band in the sky extending for about 9 degrees on either side of the ecliptic (the apparent path of the sun). The ecliptic passes through the center of the zodiac longitudinally. The ecliptic is divided into twelve rashis (segments) or signs of the zodiac, which are named Mesha (Aries), Vrishabha (Taurus), Mithuna (Gemini), and so on. The ecliptic is also populated with 27 constellations (Ashwini, etc). Each rashi consists of 30 degrees and each constellation (asterism/star or nakshatra) 3 degrees 20 minutes.
When a child is born, its exact time of birth is noted and the rashi and the star, rising in the eastern horizon at that time and place, are accurately fixed. That rashi is called the lagna (the ascendant).
Once the lagna is fixed, the rashi cakram (zodiacal diagram) is drawn, depicting the divisions of the twelve houses and the locations of the various planets in them (including the nodes, Rahu and Ketu).
Incidentally, the first, fifth and ninth houses are called trikonas (trines); second, fifth, eighth and eleventh are called panaphara (cadent); and the third, sixth, ninth and twelfth are called apoklima (succeedant).
The lagna is treated as a kendra as well as a trikona.
For example, for a Taurus ascendant, kendras are – Taurus (first Kendra), Leo (fourth Kendra), Scorpio (seventh Kendra), and Aquarius (tenth Kendra).
The planets, when found in Kendras, are supposed to be strong in extending good or bad effects. Generally, a naturally benefic planet owning a Kendra is considered bad. This is called kendradipatya dosha. This is particularly true of Guru (Jupiter), Shukra (Venus) and Budha (Mercury). If a naturally malefic planet owns a kendra, that planet is supposed to confer something good on the individual. Which planets are located in which kendras is also a factor to be reckoned with. For example, Jupiter and Mercury are said to be powerful if they occupy the first Kendra; Venus and Moon, if they are in the fourth Kendra; for Saturn, it is the seventh; and for Mars and Sun, it is the tenth and so on. This is called digbala (directional strength).
The first Kendra is the rashi rising in the east at the time of birth calculation. The fourth Kendra refers to the patala. The seventh Kendra refers to the rashi setting in the west, and the tenth refers to the zenith.
The ascendant represents the beginning of life, childhood, health, environment, physical body, character, and personality. It reflects on the general strength of the horoscope.