A 22 Degree Tidal Tail for Palomar 5
  Using Data Release 4 of the Sloan Digital Sky Survey, we have applied an optimal contrast, matched filter technique to trace the trailing tidal tail of the globular cluster Palomar 5 to a distance of 18.5 degrees from the center of the cluster. This more than doubles the total known length of the tail to some 22 degrees on the sky. Based on a simple model of the Galaxy, we find that the stream's orientation on the sky is consistent at the 1.7 sigma level with existing proper motion measurements. We find that a spherical Galactic halo is adequate to model the stream over its currently known length, and we are able to place new constraints on the current space motion of the cluster. 
C. J. Grillmair (1), and O. Dionatos (2)((1) Spitzer Science Center,   (2) INAF - Osservatorio Astronomico di Roma)