Depict realistic moonlight
Create a new layer for the moon and with the Elliptical Marquee tool, hold the Shift key so that your selection is a perfect circle. Using the Paint Bucket Tool, fill the circle with a dark yellow/orange colour. Change the Blending Mode of this moon layer to Screen. Name the layer Moon. Duplicate the layer two or three times for the glow. Scale each glow layer so it's larger than the moon layer. Make the glow layers progressively larger than the one underneath. Add Gaussian Blur to slightly soften the moon layer. Use larger amounts of Gaussian blur on the glow layers. The top layer should have the most blur. Vary the Opacity of the glow layers so they fade into the night sky. Group all the moon and glow layers. Merge the group into one layer. Load a selection of the bat layer. Cut away the moon and glow layer overlapping the bat. Paste the cut portion of the moon layer into a new layer. Lower the Opacity of the new layer so it appears behind the bat wing. Erase the bat's arm so the glow shows only through the wing.