QUOTE (tedstryk @ Oct 12 2007, 03:07 PM)
To call the new Keck images, at least from what has been released, "better than Hubble" is a stretch.
Well, don't forget, the claim was that the
angular resolution was superior to that of HST, which is true. And that's exactly what Dave was aiming for in his project to measure the motions of Hydra and Nix.
Now, if you're referring to the level of surface brightness variation in the images, then the HST images do appear to show a whole lot more variation than the Keck images. But the Keck images are also at ~1.6 microns, not in the optical or UV like the HST images (I can't recall the wavelengths of the FOC or ACS observations). What would have been surprising is if there
had been equal brightness variations in the Keck images.
And even if there had been, I don't think I'd expect the same
patterns in any case. Unless my memory has failed completely, it was the fact that there are spectral features from many different ices in the K-band (H2O, CH4, CO2 are possibilities) that let Cruikshank & others demonstrate the presence of different ices on Pluto's surface, so when you get out into the IR, the composition of the surface ices, not just the albedo of the ices, would begin to play a significant role.
Jeff