How far in space and time can we see (theoretically)? Is the zoom image always fake(or any image)?
I don’t mean glass lenses, but any lenses - why don’t we make nano scale lenses instead of those huge mirrors?
As you see, I have only questions…:smack:
“Zoom” means adjustable magnification, as opposed to a fixed focal-length optical system.
It sounds like you are asking whether there is a limit in magnification. The limit is directly related to the diameter of your optics (diffraction limit). A 10-cm (4 inch) telescope can resolve about 1 arcsecond (1/3600 of a degree). A 1-meter (40 inch) can resolve 0.1 arcsecond. Etc.
Yes - I meant magnified.:smack:(again)
And of course if the telescope is on Earth, as opposed to in orbit, turbulence in the atmosphere is the limiting factor, which is why all large telescopes are on mountains, above as much of the atmosphere as possible. Adaptive optics can compensate somewhat for the remaining atmospheric distortion.
–Mark
One other point: You can always magnify an image more. The limit is just that if your optics aren’t good enough, that magnification will be useless: You’ll just be turning small fuzzy blobs into big fuzzy blobs.
Note also that the diffraction limit depends not only on the size of your optics, but on the wavelength of the light (or other radiation) you’re using. Shorter wavelengths give you better resolution, but are often more difficult to work with in other ways. This is why DVDs (which use red light) can store more information that CDs (which use infrared), and why blue-rays can store more than DVDs. It’s also why, for images of the very smallest things, you use an electron microscope, because electrons have much shorter wavelengths than any photon of convenient energy (you could get photons with wavelengths that short, but they’d be hard gamma rays).
Have you seen the videos created by the off the shelf Nikon P900?
It’s a combination of your optics and the object.
The wider your lens or mirror the more photons it can collect. But the further an object is away, you generally get fewer photons from it. You can consider a photon as a bit of visual data. Double the distance from an object and you quarter the data? The photons are radiating out in all directions, spreading thinner with distance.
So at any instant, there is a maximum number of them that can be captured across the width of your optics.
You can do a long exposure and build up a brighter picture. But it will be less exact.
Zooming in does not increase the area of your optics. It changes focal length. Actually spreading fewer photons over a wider area. Magnifies, but dims. You reach a point where the optics magnify so much, that the image is too dim to see.
A brighter object can be magnified more. It is sending more information, so can be spread thinner.