Q: In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Passover commences on the 15th of the Hebrew month of Nisan and lasts for either seven days (in Israel and for Reform Jews and other progressive Jews around the world who adhere to the Biblical commandment) or eight days for Orthodox, Hasidic, and most Conservative Jews (in the diaspora). In Judaism, a day commences at dusk and lasts until the following dusk, thus the first day of Passover begins after dusk of the 14th of Nisan and ends at dusk of the 15th day of the month of Nisan. The rituals unique to the Passover celebrations commence with the Passover Seder when the 15th of Nisan has begun. In the Northern Hemisphere Passover takes place in spring as the Torah prescribes it: 'in the month of (the) spring' (בחדש האביב Exodus 23: 15). It is one of the most widely celebrated Jewish holidays.
A:
when is passover and how long is it