Hi Cathryn,

Thanks for sharing that. Those instruments a very delicate. I think those telescopes are part of a larger group of scopes around the world that were supposed to make Hubble obsolete. A GPS move of a single micron would throw the entire thing off. If I remember right, it creates a paralax error in the image. (Photo image intensification)
Now I'll have to dig through for my Scientific American articles. Yikes....

Glen