Here's the fifth of my planets: Neptune. I'm adding the charts for it, in case you want to make one. Stitched on 18-count Aida, it makes a three-inch square. The color chart includes the threads for all of the planets patterns, not just this one, but the colors for this planet are indicated. I'm releasing this under a Creative Commons license; feel free to share or change it, but not to sell it.
Here's another of the planets: Venus. I finished that one at Pennsic. Picture it: We're all dressed as gentlemen and ladies of the middle ages (I was dressed as a gentleman, because I hate skirts). We're sitting in class, learning about the arts of the middle ages. Around me, other ladies have baskets with them, and they're knitting Viking-style socks, or tatting lace, or reproducing Elizabethan embroideries... and then there's me, making planets.
I'll add the pattern for Venus here. For 3"x3" coasters, stitch on 18-count Aida. Click on the chart to enlarge; the thread list includes the colors for all the planets series, and the colors used in this chart are marked.
Here's another in my series of planets cross-stitch patterns: Mars. The pattern is below: notice that I've included the color palette for the whole series, and not all the colors are used in this specific chart. I stitched this on 18-count Aida, and it's a square of about three inches, perfectly sized for coasters. Feel free to use, share, or change the pattern, but please don't sell it.