Cactus flower

At its best yesterday, but still OK today.  This is Astrophytum capricorne.  The flower is remarkable for its very prominent red centre.  By blurring out the outer parts of the petals, I've removed the unsightly damaged ends to some of them.  This often seems to happen, perhaps because I don't have the moisture exactly right when the plant is in bud.  The other striking thing about this plant is its very long, curving spines.  I'll post an image of the whole plant sometime.