FT: rear firing arcs, home-made star mat

We've been playing that you can fire to the rear arc at any time.
Anyone else do this?  
What is your standard mode of play for the rear arc?

I got cheap and made my own star map playing area.  I bought a
black bedsheet and a white paint pen and dotted the sheet.  I took
some paint and dotted a few colored stars (red, green, yellow, blue).
I tried to add in a nebula with brushes but that didn't work as well.
Any other ideas for adding a nebula without spraying/air brushing?

Glen
PS. still not working, but can get a job anytime.  Enjoying the time
off!