Adaptive optics & fake guide stars

55:20star, it's going to go up by 500 to to a,000 millarch seconds, right? It's going to be 25 to 50 times worse than that theoretical limit. Okay? And so what we can do is we can do something called adaptive optics. We can correct by making a fake star here. What you're seeing is the KEK telescope and there's two lasers pointing out at where the telescope is looking and it's creating a fake star there. >> The trick is the following. >> You've got a fake star that looks like any other star. >> But we know that it came from our laser. So, it should be stationary. >> Right. >> The star and the stuff that I'm looking at could be moving and it could have dynamics. >> But I know that the laser that I'm

56:02pointing is definitely straight. >> Right. >> Right. And the laser is going through the same bit of atmosphere that the starlight is coming in. >> So if I can change >> if I have some kind of deformable mirror >> right that is taking that starlight and right in the middle I have like little ways in which I can >> change the shape of that mirror in order to keep that laser stationary. That's going to cancel out the effects of that column of the atmosphere. >> Makes makes total sense. I I have to say this because I would be remiss if we didn't. We're in between photos six and seven on the show notes and you literally anyway. >> And I literally [laughter] did say, "Oh god."

56:42>> But still don't understand that. But >> but the but the point you're saying is because we have a a fixed point from the lasers in the sky that we can then measure and basically remove the impact of the atmosphere on how we're detecting the other stars because we have a fixed point that we control that then can remove the noise that comes from the atmosphere. >> Exactly. And then we can finally get to that defraction limit. >> Got it? >> Okay, we can finally get to what the telescope is truly capable of given rally criterion. And here what we're seeing is the center of our Milky Way in infrared. >> On the left is without adaptive optics and on the right is with adaptive optics. >> My goodness, >> you can see the huge change. This is why