How to make a solar eclipse occur in Terraria Mobile edition?
In the PC version of Terraria, the only way to manually start a solar eclipse is by crafting and using a solar tablet. This item is only available on PC, so unfortunately for mobile you are not able to intentionally start a solar eclipse. You'll have to wait until one happens naturally. They only start to happen (with a 5% chance each day) after beating at least one mechanical boss.