Mario Galaxy...The Challenge Finally Arrives

Last night I managed about another hour of Galaxy, and so far tonight I've also played about an hour. This has brought my star count up to 105. Only 15 more to go! Surprisingly, I've run across a couple that are proving quite difficult to get. I even took a break to think them over. Both are purple coin challenges, where you have to collect 100 purple coins, sometimes with a time limit, or sometimes just with the difficulty of finding the well-hidden ones. One of the ones that stopped me the other night was on the Toy Galaxy. Your walking on an image of Luigi, but floor panels keep disappearing or flipping over, and many coins are suspended over a gooey pit of death. I think the secret might be long-jumping across the gaps. I didn't try that, but it should work. The other purple coin challenge is on the Ice Volcano Galaxy, and I'm completely stumped by it. I got a little over 80 coins, all the obvious ones. But there's one on a pillar that just looks like it's too high to reach. And from the very top of the level, I can see a couple of stars far away, on slightly less high peaks, and I have absolutely no idea how to get to them. I guess I'll have to try another time. Maybe I'll play some more later tonight? I don't know.