Eh?
on *:join:#Mychan:{
would only ever fire when someone joined #Mychan.

Perhaps it's the raw 366 event.
you could try using this
Code:
raw 366:[color:red]& [color:blue]#channel[/color] *[/color]:{
  if $nick($2,celtic^star,&) { .timer 1 1 mode $2 -a $me }
}