What is Ephemeris
An Ephemeris is table of values which gives the information about the position of planets, Nakshatras and Rashis. It also shows the combustion, rise of planets, direct and retrograde motion of the planets, entry of moon and other planets into sign. In Ephemeris there is also in further about eclipses ie. Solar Eclipse and Lunar Eclipse.
Indian Ephemeris System
The major difference between all Ephemeris is degree of ayanamsa. Our India astrologers mainly use ayanamsa values Lahiri, Raman, K.P., or Zero Ayanamsa. Depending on degree of Ayanamsa, calculation of Ephemeris change.
Right now ayanamsa value get approx 24°, so we should calculate or should make all the corrections based on 24° that will be more accurate and authentic. For any horoscope calculation the Ephemeris should be correct otherwise complete horoscope can be wrong. Based on wrong horoscope all predictions may go wrong. In each and every panchang we can see the part of Ephemeris.