Science Fiction Style Sky Made In Photoshop - How To

Thank you NASA for your wonderful photos (in the public domain) and DesignNocturne for a fun tutorial. The body of water is Lake Mille Lacs; located in central Minnesota. The lake is so large you can't see the opposite shore.

I basically followed Matt's tutorial but I used a soft brush instead of the lens flare.

My Notes:

Place the background image. This is a local lake photo that I took last summer.

Choose NASA images. I used Earth, Venus, Jupiter and a pretty Nebula.
I cropped the planets before placing them on the background.
Venus (reddish Planet) > Blending Mode > Lighten
Jupiter > Blending Mode > Screen
Earth > Blending Mode > Overlay.  Opacity 64%

Venus has a shadow from Jupiter. I used a soft brush and painted black in a Layer Mask.

The sun flare is a soft brush painted underneath the Earth layer. Since I used Overlay for the Earth, I erased the part that showed through with a hard brush.

I wanted a little sun refection on the planet so I painted some of the edge with a soft brush on the layer above the Earth layer; then lowered the opacity.

I placed the Nebula image on a new top layer. Blending Mode > Screen.

Use a layer mask and a black brush to remove the stars from on top of the planets. If you have a lot of stars near the horizon you can use the gradient tool to fade them.

I liked it washed out but you can change the contrast easily by moving the sliders on an Adjustment Layer > Levels.