Step 1 determine what month of the night sky you want, we chose November since that is when our anniversary is. Google month star map and find the image you like I chose the following because I thought it made a nice Milky Way outline. https://www.google.com/search?q=november+star+map&hl=en&client=safari&source=lnms&tbm=isch&sa=X&ei=CWlYUYOKJJLU8wSd4ICABQ&ved=0CAgQ_AUoAQ&biw=320&bih=504#biv=i%7C40%3Bd%7C55tGItOX03CgXM%3A
Step 2 Cut and paste image into the paint program that's on every computer from there you need to MIRROR the image or you star ceiling will be backwards on install. Also, if you used a black background map you meed to INVERT the colors or you will be buying 3 black ink cartridges before the project is over.
Step 3 You need to scale the image the size of the ceiling ours is 16'Lx8'W. to be honest I can't quite remember if I did this by cut and paste into a PDF file or if I used poster razor, anyways I used this link http://m.instructables.com/id/Star-Map/step10/Attaching-the-map-to-the-back-of-the-substrate/
as guide to do all of this.
Step 4 Cut and Paste image into PDF and print options select PRINT TILES Make sure your printer prints the page numbers or you will be lost and that it prints reverse order for example 3,2,1 instead of 1,2,3.
I have still have our scaled November map if anyone wants a copy, I am doing these steps from memory, so if anyone had any questions just ask, it really isn't that big of a deal once you get started.
We decided against a FOSI once we got a quote from them and realized that we could do it for much cheaper. Also, I will post later on how to make a homemade illuminator.