A Solar Eclipse is an event that has a 1/25 chance of replacing a regular day when Hard Mode is active in a world. This event will last for the entirety of the day which it happens on (15 minutes). A solar eclipse is heralded by the message, "A solar eclipse is happening!", and a change in music.
A Solar Eclipse can happen at any time after the player has defeated the Wall of Flesh and any of the mechanical bosses (The Twins, The Destroyer, or Skeletron Prime.) When a Solar Eclipse happens, monsters from the chart below will spawn in the place of regular monsters in all surface biomes.
The monsters that spawn have a chance to drop the Broken Hero Sword which is a material vital to the late-game melee-weapon user, due to it being used to craft the True Excalibur, True Night's Edge, and Terra Blade.