Since its discovery at Palomar in 1992, the Guitar Nebula has been regularly observed. Read more about the Nebula, and see some pretty pictures, here.
While a sequence of Hubble Space Telescope images makes the proper motion of the nebula most obvious, maybe you can see the motion in the sequence of Palomar images as well? Hint: place your cursor on the nebula tip! (Unfortunately, the 1992 data are not of astrometric quality at the tip.)
Note that the motion of the tip is a probable upper limit to the expected motion anywhere else in the nebula, so large scale changes in the Guitar body are not expected (yet).
See more about the Nebula here, including the HST images.
Last modified: 7 Feb 2002