How do they interrogate the witnesses? The pair that arrives first is interrogated first, and the elder is brought in and they say to him, “Tell how you saw the moon —- facing the sun or away from the sun? To its north or to its south? How high was it? And which way was it leaning? And how wide was it?”  If he said, “Facing the sun,” he said nothing.  Then they would have the second [witness] brought in and interrogate him. If their words are found to coincide, their testimony is valid.  And they ask the rest of the pairs [of witnesses only the] main points; not that they needed them, but so that they should not leave disappointed, in order that they should be accustomed to come.

The head of the beis din says, “It is sanctified!”  And all the people respond after him, “It is sanctified! It is sanctified!”  Whether it appeared at its [expected] time or whether it did not appear at its [expected] time, they sanctify [the day].  R’ Elazar bar Tzadok says: If it did not appear at its [expected] time, they do not sanctify, for it has already been sanctified by Heaven.