Take last week's press release from the University of Cambridge Institute of Astronomy. The lede:
A team of astronomers have taken pictures of the stars that are sharper than anything produced by the Hubble telescope, at 50 thousandths of the cost.
The Hubble team bit back, pointing out that release's claim is a half-truth, at best. The Cambridge camera, dubbed "Lucky," can achieve 50 milliarcsecond resolution--twice as fine as Hubble--but only in a tiny fraction of split-second-exposure frames. The "good" frames have to be added up to yield a useful image. To truly beat out Hubble, the Lucky camera has to stare at the same section of sky for much longer.
This isn't just a matter of scientific pride: It's a money thing. If policymakers and the public believe that a ground-based system like Lucky is better and cheaper than Hubble, why would they shell out extra cash for the space telescope?
The fact is that ground-based and space-based telescopes are complementary instruments, not competitive ones. Earthbound telescopes have the advantage of size: The bigger a telescope is, the more sensitive it is to faint objects. Space telescopes are smaller (Hubble's mirror is just 2.4 meters in diameter; Keck, for instance, is 15 meters wide), but they don't have atmospheric scattering to contend with, so they can snap clearer pictures.
The Lucky camera does its best to cancel out that scattering by skimming sharp frames from a big pile of blurry ones. But the intimation that systems like Lucky will make space telescopes obsolete is, as Hubble spokesman Ray Villard put it to Alan Boyle, "greatly premature."
According to this great explainer from Nature News, the Lucky team is abashed and admits that the press release "did kind of hype it up."
But it's a shame, and now the facts of Lucky's real technical innovation are lost in the noise.