You can send 1 Spell Trap from your hand or field to the GY; Special Summon 1 LIGHT Spellcaster Tuner from your Deck. If a Spell Trap(s) is sent to your GY to activate a monster s effect, while this card is in your GY (except during the Damage Step): You can Special Summon this card. You can only use each effect of Astellar of the White Forest once per turn.