Lord siva's star is thiruvathirai. In 2013 thiruvathirai star occurs in a amavasa in tamil month of aani on 7.7.2013 sunday. Separated couples who want to unite can visit near by siva temple on this day and should offer abhisegam to lord siva. They have to chant omsivasivaom mantra during abhisegam.After that they have to make archanai in both of their names and star and has to offer Rs.108 as guru dhakshina to temple priest.Separated couples have to continue this for 6 months.One should eat strictly vegetarian food only.Before 7th amavasai, separated couples will be united.
thanks to aanmiga kadal blog.