The discussion centers on the use of lasers in telescopes for capturing images of the universe, particularly focusing on the principles and limitations of laser technology in astronomical applications. Participants explore the concept of laser guide stars and the challenges associated with using lasers for imaging distant celestial objects.
Participants express differing views on the practicality of using lasers for capturing images of distant celestial objects, with some agreeing on the limitations of the initial understanding while others emphasize the specific applications of laser technology in astronomy.
Participants highlight limitations such as the challenges of maintaining beam collimation over vast distances, the necessity of dedicated mirrors for reflection, and the timing issues associated with laser ranging experiments.
I don't think that's what it is. You're probably thinking of this:pvk21 said:it shoots out laser is space and get images from reflected light.
A small but relevant fraction of the photons in lunar laser ranging comes from the lunar surface around the retroreflectors. Not with such a nice timing as the surface is not completely flat, but I guess it could be possible to do lunar ranging without retroreflectors today.Bandersnatch said:You can't really use lasers like what you described, as it's impossible to maintain a tight, collimated beam over large distances, impossible to get a reflected beam that gets back to you without a dedicated mirror (like with the Lunar Ranging experiment), and most importantly, impossible to wait a number of years for your beam to get to the target, bounce back and hit the aperture of your telescope. All you have is a night.