Panchang is similar to an Ephemeris. Panchang is composed of two words: - 'Paanch' (five) & 'Ang' (parts). It means something which has got five parts. Five parts of panchaang are: - Tithi, Vaar, Nakshatra, Yog & Karan. Every year a new panchang is released. It gives details of movement of planets in that year like: - vakriya, maargi, udit, aast, sankrantis of all planets, aamavasyas, poornimas, solar eclipses, lunar eclipses, various festivals, vrats (fastings), snaans in reverred rivers of India, melas (fairs) in various parts of India, sun rise & sun set timings of each day of a particular place from which that panchang is generated. Also planetary positions of each day in morning 5:30a.m. is mentioned. Other useful information on Astrology is also given.
Panchang was of heavy importance for astrologers in the past because it was the only tool which was used to make horoscopes earlier, as it consists of necessary astronomical information required to make horoscopes. But nowadays various computer softwares are available which can do necessary arithmatic to generate hooscopes in a fraction of a second & moreover with great accuracy.