I'm wondering what is meant by a religious calendar?
Our standard calendar is based on the sun; the Chinese calendar on the moon. I think the Jewish calendar is based on the moon- someone correct me if I'm wrong (I well could be- I can't remember). The Maya calendar was based on the sun and is more accurate than our own. I don't know of any calendars based on the stars, though astrology links calendars with the stars.
Or do you mean a yearly calendar of holy days? Neo-pagans of various sorts mark the year by eight sabbats- eight holy days that are linked to the sun and seasons, including summer and winter solstice.
Not sure if that helps at all...