The difference is: the ghost is driven by his tendencies (I just wrote ‘his,’ he is actually neither male or female but his tendencies may look him like either male or female or some other distorted figure), but the celestial being has certain level of awareness, certain level of discretion of right and wrong, his purposes is more into the evolution — on the other hand, the purpose of ghost is to cater his tendencies.

Though both are made of the same stuff but the degree of awareness puts them pole apart. Celestial beings are the people who have been on the spiritual path or somehow they lived and died in certain level of awareness which went along with them in that realm, and now in that realm they are working for their evolution. But the ghosts doesn’t work for his evolution, as still his kamas (the tendencies) are too much, he is just into the fulfillment of them somehow; though he doesn’t have the mind but he is drawn where he finds his tendencies can be fulfilled — that’s why black-magic guys trap them easily by manipulating their tendencies.