Step 1: Materials Required
1 Plastic Glass
1 thin needle ( you can use anything which is pointed and has more thickness than the needle)
1 medium thickness nail
1 flashlight (mine was Blue LED based. I don't know whether ordinary bulb flashlight will work or not since for "Diffraction" and "Interference" to take place(on which my planetarium is based) you need a monochromatic light .Simply just use a LED flashlight.