I have this one -> Sega Homestar Original Black - Home Planetarium - Star Projector
My husband got it for me for Christmas last year, honestly I don't use it too often. It takes forever to get the positioning right otherwise it only shows on half the ceiling and you can't have the TV on which I need to fall asleep. But it does work really well and you really feel like you are out under the stars.
Definitely cool. The last thing I do before I go to sleep is to turn on the music channel area, New Age on my TV and turn the volume all the way down. After a minute the screen goes dark and the music helps me go to sleep. I feel a little safer and more secure with the music in the background. I wish they had a lullaby channel but they don't.
Those things are nice, but anything that produce blue light should never ever be used in a room, blue light prevent sleeping, read about it using google, you'll see any kind of blue light is just enough to prevent you from sleeping well through the night, my aunt throwed the blue nightlight and projector out of my nephew bedroom (he's going to be 4 in april) and replaced the night light with a red small light, and since she did it, my nephew sleeps a lot better), even the tiny screen of an alarm clock that would be blue would be enough to prevent the sleep you need.
I have often wanted something to gaze up at when I'm in baby-mode and trying to drift off to sleep. Mobiles are out of the question as I don't have a crib. This certainly looks like something I could invest in to scratch that itch.