Celestial robes are magic based armour. It has quite reasonable stats and due to its low cost, is an excelent choice for beginners. These robes require a Magic level of 90 or higher to equip. There are two types of these robes in the game. One is bound, while the other is not. You can tell which is which as the bound robes will have a '(b)' at the end of their names. There is no difference in appearance or stats between these two sets, the only difference is how they were obtained.
The unbound robes were previously obtained from the participation shop, however, they have since been removed. Thus they are no longer obtainable, apart from trading with players who had bought them before.

Obtaining Celestial Pieces

The only way to get the bound version of these robes is by killing the Ice Queen boss. The Ice Queen has a large amount of items in her drop table, and the Celestial Pieces are one of the rarer drops. So it may take a very long time if you are hunting for a specific piece.