Adding lighting effects and moons (5 of 6)

The image looks pretty good, but a few final touches will pull everything together. Since Jupiter is acting as a light source in the sky, some light wrap around the edges of the background ice will help to suggest its luminosity and make the ice look translucent. Load a selection from the ice wall masks, create a new layer, and fill it. The color doesn't matter. 

Add Inner and Outer Glows to this new layer. For once, keep them in Screen mode. Pick some orangey-pink colors from the background. Now Reduce the Fill of this layer to 0% so that only the glows are visible. The glowing edge and light wrap should be concentrated on the ice in front of Jupiter, so add a mask to this layer and put black linear gradients on the edges to hide the effects there. Make sure the Layer Mask Hides Effects option is checked. Now the glows are only visible in the middle, where the mask fades to white. To further complete the lighting effect, Jupiter itself needs a glow. But an Outer Glow using all the pixels on the planet's layer won't work, because the left side is in shadow. We need to make a selection from just light lit areas.

Turn off the ground layers and go to the channels. Duplicate the red channel, since it has the greatest contrast between Jupiter and the sky. Use a Levels adjustment and move the highlight slider to the left to make it mostly white. Move the shadow slider to the right to make sure the sky is entirely black. Load a selection from this channel and feather the edges by going to Select >Modify >Feather. Enter a large number to give the selection a very soft, blurred edge. Create a new layer and fill it with a rust color picked from Jupiter. Change the layer's Blend mode to Color Dodge and lower the Fill to 60%. Give it a large Outer Glow in Screen mode, using an orange picked from Jupiter. Load a selection from the ice wall's mask, add a mask to the new planet glow layer, and fill it with black. This time, leave Layer Mask Hides Effects unchecked so that the glow follows the edges of the jagged ice wall.

A couple of moons orbiting Jupiter is really what this image needs. Astronomers may disagree with the placement, but they will look cool. I used photos of Io and Ganymede. To tie them into the scene, add some Layer Styles. A little dark Inner Glow in Multiply mode should do the trick. Give them an Inner Shadow using the settings shown. You also may want to add a Bevel and Emboss and Color Overlay. Create a layer in Multiply mode for the shadow that Io casts against Jupiter. For a hint of reflected light on the moons from Jupiter, load selections from the moon layers, create a new layer, and fill it with a color. Again, what color you use doesn't matter. Set the Fill to 0%. Use an Inner Shadow with these settings to give the moons a rimlight coming from Jupiter. At this point, the image is just about complete.