Islamic
Commonly on the seventh day, with the aqiqah
The practice most widely followed is that a child is named on the seventh day after birth, alongside the aqiqah — the sacrifice and the shaving of the head. Naming earlier is also reported and is not held to be wrong; the seventh day is the common practice rather than a universal requirement.
Names of the prophets are favoured, as are the names formed with ʿAbd — servant of — followed by one of the names of God: ʿAbdullah, ʿAbd al-Rahman. The corresponding prohibition is firm and worth stating plainly: a name that makes someone the servant of anything other than God is not used.
Meaning is the usual criterion. A name is chosen because of what it means and what it carries, and names with poor or boastful meanings are changed — there are well-known reports of the Prophet renaming people on exactly that ground.
Astrology? None. There is no astrological element in Islamic naming, and this page does not suggest one. The abjad or jummal value of a name is a folk practice found in some communities, not a religious ruling — the site's own abjad calculator is offered as arithmetic, not as guidance.