A great artifact in the collection is the Hale Telescope's old Prime Focus Spectrograph.
A cool thing about the display is that you can actually see one of the spectra captured by the instrument.
These spectra are so tiny that they can only really be inspected with a microscope. In the image above the spectrum of radio galaxy 3C 327 isn't the feature that looks like bar codes, it is what you see between the "bar codes" which are reference lines.
I shot a short movie of the exhibit with my iPhone. You can see it below:
Palomar shows up in a number of other places as well. Perhaps the most notable artifact is the prism for the 4-Shooter camera. The 4-Shooter, tested with the 200-inch telescope, was the prototype instrument for the Hubble Space Telescope's Wide-field Planetary Camera known as WF/PC (pronounced "wiff pic"). For anyone interested in learning what it was like to observe with the 4-Shooter at Palomar in the 1980s, I highly recommend the book First Light by Richard Preston.