Vṛścik‌‌‌a preceded by the solar month of Tulā, and followed by the solar month of Dhanu. The Vrschika month is called "Kartigai" in the Tamil Hindu calendar. The ancient and medieval era Sanskrit texts of India vary in their calculations about the duration of Vrschika, just like they do with other months. For example, the "Surya Siddhanta" calculates the duration of Vrschika to be 29 days, 11 hours, 46 minutes and 0 seconds. In contrast, the "Arya Siddhanta" calculates the duration of the Vrschika month to be 29 days, 12 hours, 12 minutes and 24 seconds. The Indian solar month names
Lunar phase eastern horizon at one moment sees it on the western horizon about 12 hours later. This adds an oscillation to the apparent progression of the lunar phases. They appear to occur more slowly when the Moon is high in the sky than when it is below the horizon. The Moon appears to move jerkily, and the phases do the same. The amplitude of this oscillation is never more than about four hours, which is a small fraction of a month. It does not have any obvious effect on the appearance of the Moon. However, it does affect accurate calculations of