This was a personal challenge inspired by a friend's comment about my latest series of photos of my frosty windows. The idea grabbed me, and I took off with it, to turn a bit of sparkly frost into a fake photo of deep space. After several experiments, I turned out one that is not only the best so far, it was done mostly with the simplest tools.

1 Crop out a selection
2 Add black background layer
3 Add alpha transparency to photo layer
4 Select by color and delete until only the brightest spots are left (can be tricky, but worked well with this photo)
5 Gaussian blur slightly (2px)
6 Copy layer, select transparent, grow selection enough to delete smallest speckles and trim large "stars"
7 play with "Sparkle" (Lighting effects) filter on the last, simplified layer until there are some nice subtle rays

All layers are included in the final image. A little hand-retouching turned one odd-shaped "star" into a galaxy.

That's really clever. It does remind me of the Hubble deep field. This is the Hubble Extreme Deep Field

I visited the Hubble gallery to check my "authenticity"

Very nicely done.

That worked out really well, Nice job.

I've simplified the process a little. First step is to put a black layer under the frost, then change the frost layer to "Hard light"--that usually brings out the stars right away, and leaves better nebulas. Copy visible, paste as new layer, and start touch-ups from there.

Also works on sparkly snowbanks, like this dirty leftover April snow.