5 ms·

$2m is the cost on Starship's Wikipedia page, which implies 10 Hubble masses. Now, I am not talking about taking 216 mirrors and combining them into a single mi

$2m is the cost on Starship's Wikipedia page, which implies 10 Hubble masses. Now, I am not talking about taking 216 mirrors and combining them into a single mirror pointed at a single camera, but actually 216 self-contained mirrors and cameras. That is, whether they're put closer together or further apart, they'll be interferometry based. What's important isn't how well-aligned they are, but how well they know how they're aligned. I think the reason these things keep getting built on Earth is because until now no one has dared to dream of putting that much mass in orbit for that cheap.

ncmncm 7y ago
Self-contained cameras are not good enough. You need to actually quantum-interfere the photons from one optical path with those from the other paths to get the effect of the larger resolution. You can do this with optical fiber, a pixel at a time, for sufficiently slowly changing scenes. Each big mirror is then responsible for collecting enough photons so they can all interfere constructively and deliver a useful brightness level. The output goes through a diffraction grating to get a spectrum for each pixel, so they need it pretty bright.
- Johnjonjoan 7y ago
  Is this what they did to bring us the high resolution picture of a black hole? If not could that method be used by these hypothetical hubbles?
  - martythemaniak 7y ago
    It sounds like the parent is referring to a specific type of interferometer, because yes, this is what they used on the EHT and it did not have any such entanglement or quantum effects.
    - ncmncm 7y ago
      Actually regular light-wave interference suffices, but it's quantum anyway, just because that's how light is.
  - sandworm101 7y ago
    >> Is this what they did to bring us the high resolution picture of a black hole? If not could that method be used by these hypothetical hubbles? That was using radio waves, something that can be measured in each telescope, saved as data, and then combined in a computer. At optical wavelengths we cannot record the data as accurately/quickly and so must instead use extraordinarily precise mirrors and fiber optics to join the light from each telescope in real time. These links must be accurate in distance to within a wavelength.

ncmncm 7y ago

Self-contained cameras are not good enough. You need to actually quantum-interfere the photons from one optical path with those from the other paths to get the effect of the larger resolution. You can do this with optical fiber, a pixel at a time, for sufficiently slowly changing scenes. Each big mirror is then responsible for collecting enough photons so they can all interfere constructively and deliver a useful brightness level. The output goes through a diffraction grating to get a spectrum for each pixel, so they need it pretty bright.

Johnjonjoan 7y ago
Is this what they did to bring us the high resolution picture of a black hole? If not could that method be used by these hypothetical hubbles?
- martythemaniak 7y ago
  It sounds like the parent is referring to a specific type of interferometer, because yes, this is what they used on the EHT and it did not have any such entanglement or quantum effects.
  - ncmncm 7y ago
    Actually regular light-wave interference suffices, but it's quantum anyway, just because that's how light is.
- sandworm101 7y ago
  >> Is this what they did to bring us the high resolution picture of a black hole? If not could that method be used by these hypothetical hubbles? That was using radio waves, something that can be measured in each telescope, saved as data, and then combined in a computer. At optical wavelengths we cannot record the data as accurately/quickly and so must instead use extraordinarily precise mirrors and fiber optics to join the light from each telescope in real time. These links must be accurate in distance to within a wavelength.