M51 / Arp 85 - The Whirlpool Galaxy

M51 (NGC 5194), the famous Whirlpool Galaxy in Canes Venatici, is one of the most iconic interacting galaxy systems in the sky. Its nearly face-on orientation and sweeping grand-design spiral arms make it a favourite target, but what truly makes it special is the ongoing tidal interaction with its companion, NGC 5195. This gravitational encounter pulls out delicate streams of dust and gas, enhances star formation in the spiral arms, and gives the system its distinctive distorted structure.