PTI similarly is designed to operate in a completely automated fashion, for a full night without human intervention. The importance of operating a real observatory, instead of just designing the operations sequence on paper and in simulation, is that we encounter real life problems. There are very few fully automated interferometric observatories, that align themselves and phase themselves on starlight. Practical experience with an operational observatory, is invaluable, given the radical difference between operating a telescope and an interferometer. Shown here is the Palomar Testbed Interferometer site as viewed from the external catwalk of the 200-inch Hale telescope.
Future plans call for a third siderostat to be installed off the left side of the image.