1,246. Traveling to Court on Shabbos

Hilchos Kiddush HaChodesh 3:1

When witnesses see the moon, if traveling to the court is a journey of that night plus the next day or less, they should go and testify. If the distance is greater than this, they should not go because their testimony won’t be delivered until after the 30th day. The month will have already been declared full, rendering their testimony moot.

Hilchos Kiddush HaChodesh 3:2

The witnesses who see the moon should travel to the court to testify even on Shabbos, as is derived from Leviticus 23:2, “that you shall proclaim in their time.” Whenever the Torah says to do something “in its time,” Shabbos is superseded. Shabbos is only superseded in order to declare Rosh Chodesh Nisan and Rosh Chodesh Tishrei so that we may observe the holidays in their proper times. When the Temple stood, Shabbos was superseded in order to declare any Rosh Chodesh because the musaf offering that was brought on Rosh Chodesh also supersedes Shabbos.