How to catch Cresselia (If possible) in Diamond?

vey annoying, likes to run, can be a b**ch to catch but heres how i did it! keep a strong pokemon (over lv 50!)that knows block or mean look in your party (mine was a gengar lv.59) i got its health in the red, used hypnosis, and then caught it! BUT!!! (heres the annoying part!) it shows up at RANDOM!! anywhere in the nation!!! grrrr......sorry...ANYWAY!!! good luck and hope you dont break your ds in fury.....like i almost did.....hope i helped!!!!!

Edit :After obtaining the National Dex, talk to the boy in Canalave City and then talk to the sailor to sail to Fullmoon Isle. Talk to Cresselia there and it will then run away, so you will have to chase it using your Marking Map Poketch app. Only one. Use a pokemon with the move mean eyes then do what you normally do to catch pokemon. Ironically i used a diiferent way opposite to that. what i did was get a normal pokemon to weaken it to red then the next time i meant it i put it to sleep then the next time i meet it i used a Quick ball(which worked) To find it in the wild use your poketech and keep going left right left right from one map to another i did it from jublife to route 203 then when in sight on my 3rd attempt i caught it! guess i was lucky but anyways if you hurt it it will show in the next battle too same goes for stats! Good luck catching it

when u get the national dex. and beat the elite four go to the canavele city and then go to where the sailor lives. hell tell you that his son is sick. go inside and then talk tot he kid and then the dad will come in and take you to the full moon island. you will encounter creseilia but it will run away. so you have to catch it when you encounter it ont he wild

once you have obtained the national pokedex go to sailor eldric's house in canalav city. His son will be sick and you must go to full moon island to get the lunar wing. once you get to the island the only thing there will be the cresselia. it will not stay on the island however you must chase it across sinnoh similar to what was needed to be done to catch raikou, suicune and entei in gold/silver, latios/latias in ruby/sapphire, and mesprit in diamond/pearl. your best options are to either use a master ball or use a pokemon with the attacks mean look (golbat) or block. or if they have the special abilities areana trap (trapinch) or shadow tag (wobbuffet).

you first have to get the national dex by seeing all the pokemon in sinnoh then u go to conclave city and talk to the sailor guy and hell say his sons sick and ask u if u wanna help, say yes and hell take u to full moon island where u see cresselia it runs away and u gotta catch it like mespirt (randomly in sinnoh)