Nebula has symbol NGC281. It was discovered in 1883 by E.E. Barnard, who described it as "a large faint nebula, very diffuse". The nebula is visible in amateur telescopes under dark sky.
NGC281 is a star formation region. Inside there is young open star cluster IC1590 that contains hot, blue stars. It is placed about 9500 light years from Earth in Perseus spiral arm of our Galaxy. The largest Bok globule in Pacman nebula is about 2.6 light years large.
Picture above is shot in hydrogen alpha emission line, so you can see how the actual hydrogen clouds that are excited to shine with nearby hot stars.
Another one is close up of some Bok globules:
The first picture in this entry is false bicolor composition with additional frames made in oxygen emission lines.