How To Catch Jirachi

So, you want to know how to catch Jirachi...well, first I will give the Requirements.
You NEED 200 pokemon at least.
Ok, if you have 200 pokemon, go to the Mossdeep City (are u playing Pokemon Ruby,Saphire,or Emerald?)space center. Talk to the scientist at the window looking out...he will say "We are launching rocket #???" and then ask you if u want to be on the shuttle. Say "Yes", and you will be in the shuttle. Then you can catch Jirachi, and possibly Deoxys.