Brood Astronomer is a rare Creature — Insect Scientist card from Alchemy: Edge of Eternities (YEOE), collector number 18.
When this creature enters, you may sacrifice a land. If you do, draft a card from the Planets Spellbook and put it onto the battlefield tapped. {T}: Add one mana of any color. If you control a Planet with twelve or more charge counters on it, add three mana of any one color instead.