"The set of maps covers the stars down to magnitude 7, which only a few people with super eyes can see with the naked eye, and only under extremely dark, rural skies. (Most can see down to 5.5.) They also cover many of the brightest deep sky objects you can see with a moderately-sized telescope."
Update: Bernard sez, "I converted the CC-licensed star-charts from Pdf to Jpg and resized them to the biggest size that would still work on a PSP. I have uploaded them to my Flickr site."