I used about 1/2 mile of fibre, but it will depend on the density of stars and the location of your light source. (Sorry for the late reply.)
That's great. Did you do anything differently? It looks really good.
Hi, what have you been using it for? I used 0.75mm pmma. For smaller projects, any old fibre should be optically fine. If you buy it from UFO or Starscape then you'll get good fibre, but I think all of the 0.75mm comes from China. The bigger stuff is made here. If you want to get more technical, the mitsubishi datasheets are good, and often their fibre is specified because of them. I think all of the good manufacturers make to similar specifications, but Mitsubishi write a good datasheet! What was the problem with the fibre you used?
Unfortunately the fibre used here is not glass.