One would expect the Welsh to have the names of the planets somewhere in their culture. Although modern Welsh planetary names follow the traditional pattern of Romano-Norse names that correspond with the seven days of the week, the Welsh gods and godesses have different attriubutes to the conventiol deities as follows:
Sunday: Sol/Helios – Llew
Monday: Selene/Luna – Mani – Ceridwen
Tuesday: Ares/Mars – Tiw/Tyr – Nudd
Wednesday: Hermes/Mercury – Wotan/Odin – Llew
Thursday: Zeus/Jupiter – Thor- Taranis
Friday: Aphrodite/Venus – Freya/Frigg – Gwene
Saturday: Cronus/Saturn – Tyr – Tegid
THE SUN : most commonly associated with the god Llew, son of Arianrhod. Who descends to his lowest point of the year at midnight on the first of May and begins his ascent on the first of August, thus his ‘disappearance’ brings the summertime, the ninety-two days between Beltane and Lughnasadh.
Traditionally the god Beli has some connectionwith the Sun – his name appearing in the word Beltane. At the same time some modern sources claim he is also associated with Samhain, the start of the Celtic year.
THE MOON: most commonly associated with the goddess Ceridwen, the mother of the bard Taliesin. At the same time, the god Don and the goddess Blodeuwedd, are not infrequently, associated with its waxing and waning, with Arianrhod goverining the full moon.
MERCURY: Llew as the planet which has very close links with the Sun.
VENUS: is most commonly associated with the goddess of love Gwene or Gwener, which maybe shorthand for Gwinevere, from Arthurian sources. The planet is also associated with Branwen the sister of Bran the Giant. Which although, an ancient association is not to be trusted completely.
MARS: is associated with the god Nudd Llaw Ereint, the father Gwyp spring Nudd who later became the king of Annwn, the Underworld.
JUPITER: this is the almost forgotten god Taranis from the Welsh Taran meaning ‘thunder.’ In some late Roman inscriptions found across southern Britain, Taranis is identified as Jupiter, who from his abode in the sky governed the weather. It is likely that this god was introduced into Iron Age Britain from Gaul and accepted into the Celtic pantheon by the Romano-British period.
SATURN: is associated with the god Tegid, the husband of Ceridwen, also known as Tegid Foel who becomes (by proxy) of the bard Taliesin.
The associatios can’t be voUched accurate, given that so many of these putative gods and goddesses cross over in many Welsh myths.
NOTES:
Martin Griffiths, Dark Land, Dark Skies.
TAROT ETCETERA 