Reduce the planet grid effect

#1631.

This doesn't fix the problem, it just reduces the effect.

With:
![screenshot-20130211-013620](https://f.cloud.github.com/assets/115749/144077/844588e2-73eb-11e2-9183-1deec761e474.png)

Without:
![screenshot-20130211-013633](https://f.cloud.github.com/assets/115749/144076/842fcaca-73eb-11e2-8a14-5695ed3db46a.png)