lua - Attempt to index local 'star1' (a nil value) -- I've researched everywhere and don't get it -

i've been stuck on while , need help. i'm trying have these objects spawn on screen , allow player drag them around want.

at moment random objects flow onto screen, when try click on 'star1' error :

attempt index local 'star1' (a nil value) how should properly?

here code:

display.setstatusbar(display.hiddenstatusbar)  local physics = require('physics') physics.start() --physics.setgravity(0, 0)   _w = display.contentwidth; --returns screen width _h = display.contentheight; --returns screen height  local bg = display.newimage('bg1.png')  local startable = {}    ship = display.newimage("head.png")     ship.name = "ship"     ship.x = -80     ship.y = 100     physics.addbody(ship, { issensor = true })     ship.bodytype = 'dynamic'     shipintro = transition.to(ship,{time=4000, x=200})     ship.width = 40     ship.height = 40     ship.gravityscale = 0  local star1 = display.newimage("acorn")     star1.name = "star1"     physics.addbody(star1, { issensor = true })     star1.bodytype = 'static'    function initstar()     local star1 = {}     star1.imgpath = "acorn.png"     star1.movementspeed = 10000     table.insert(startable, star1)      local star2 = {}     star2.imgpath = "enemya.png"     star2.movementspeed = 12000     table.insert(startable, star2);               local star3 = {}     star3.imgpath = "star3.png"     star3.movementspeed = 14000     table.insert(startable, star3) end       function getrandomstar()     local temp = startable[math.random(1, #startable)]      local randomstar = display.newimage(temp.imgpath)      randomstar.myname = "star"      randomstar.movementspeed = temp.movementspeed     randomstar.x = math.random(0,_w)      randomstar.y = _h + 50 -- start star off screen     randomstar.rotation = math.random(0,360)      starmove = transition.to(randomstar, {         time=randomstar.movementspeed,          y=-45,         oncomplete = function(self) self.parent:remove(self); self = nil; end         }) -- move star end     function star1:touch( event )     if event.phase == "began"           self.markx = self.x            self.marky = self.y        elseif event.phase == "moved"          local x = (event.x - event.xstart) + self.markx         local y = (event.y - event.ystart) + self.marky          self.x, self.y = x, y    -- move object based on calculations above     end      return true end  star1:addeventlistener( "touch", star1 )  startimer1 = timer.performwithdelay(1700,getrandomstar, 0) startimer2 = timer.performwithdelay(2300,getrandomstar, 0) startimer3 = timer.performwithdelay(2700,getrandomstar, 0)        initstar() 

instead of code:

  local star1 = display.newimage("acorn")     -- think line no: 27 

try following:

  local star1 = display.newimage("acorn.png") --[[ add image name                                                     suffix/extension  --]] 

keep coding............. :)