Super Mario Galaxy Strategy Guide Part 26: The Purple Coin Galaxies at the Fountain Dome
Space Junk Galaxy
Purple Coin Spacewalk
Okay, this is the deal. You need to get 100 coins, and you must do this by grabbing the 10 groups of 10 purple coins that are set up in bowling pin formation. You only have two minutes, so you have to work very, very fast.
What I did is I started in front and worked from the first right at the beginning, to the second row left, then third on the second row right. The reason why I did this was so I could avoid doubling back as much as possible. It meant doing some weird jumps, but you do make it. It also means doing a few circular movements so you can get all ten coins in one shot.
The path forms itself, but some variations are odd and you should usually take the most simplest of paths on the way back. Get the star, and if you’re lucky, you’ll barely make it.
Battlerock Galaxy
Purple coins on the Battlerock
Okay, this one is very tricky and you will need to stay on a very specific path in order to win. You will need to grab all 100, and if you miss one, you might as well return to the observatory, because you cannot win the level unless you have all 100. The cannon fire can be distracting, but it can be taken out with Star Bits that can be obtained from the nearby wall.
You will start out just waiting for coins to come to you. You will have to make two jumps to get the coins higher, then grab the group of six very fast.
Grab the other coins as they come, and the next group of six. Your thing will then pass under a railing, so follow the path of the coins, and make certain to grab every one. You will soon get to a point where you are upside down. After you grab the group of six, run quickly to the other side and grab the next group of six.
After that, a difficult backward somersault will be required to get the next coin, so make sure to make it. You will then need to make another jump soon after that, and a very precise backward jump after that. Once you get to where you need to go, jump to the other side and talk to the robot, who will give you a star if you have all 100.