Nikon D3100. How to change image type from JPEG to RAW?

I want to change the image file type from JPEG to RAW. I read that RAW is better for taking pictures of stars or the moon, and i can't find the setting on my camera.

ANYBODY KNOW!

Time to spend some quality time reading the manual

It is the same control that changes the size of JPG images (Fine, Normal, Basic, etc).

Just like the D3000, the Nikon D3100 can shoot not only JPEG or. NEF RAW image files, but can also simultaneously record each image in both formats. Three JPEG compression levels are available, although only the highest quality Fine compression level is available when shooting in RAW+JPEG mode.
Click Menu button in Camera (recording mode). Go to Image Quality setting where you can select
JPEG, RAW, or both

Why haven't you picked up your Owners Manual yet? So many basic camera operation can be found in the Owners Manual including on how to change the image file from JPEG to RAW simply by reading the Owners Manual. If you don't have the Owners Manual you can get the PDF version of the Owners Manual

Try Looking at Page 64 of the Owners Manual
http://www.nikonusa.com/...100_EN.pdf

I have photos on my camera that are RAW but to print them in a store then I need to change them to JPEG. Can this be done on the camera?