Having recently chanced upon the Bortle Scale, I'm intrigued to know just how much increase there would be in stellar luminosity as observed from space - say, from the ISS. For the sake of argument, I'm discounting the effects of spacesuit visors etc. Many thanks.

 

 

http://en.wikipedia.org/wiki/Bortle_scale

At the best terrestrial observation places and for proper wevelengths, our atmosphere is essentially transparent, and space observatories would improve little on that.

 

Satellites are irreplaceable for:

- Wavelengths that don't reach Earth's surface

- Very constant transmission, say to detect exoplanets by the occultation of their star, or for star seismology

- Observations periods of several days without interruption

- Lack of atmospheric turbulence, improving the resolution.

 

The atmospheric turbulence was a fundamental limit to the resolution before adaptive optics was available, that is, as Hubble was being developed. When Hubble was launched, adaptive optics began to compete with satellites, especially because ground telescope are bigger so they offer a better luminosity. Presently (James Webb) a space telescope must be huge to bring a resolution advantage.

Yes, I'm looking forward to the advent of the James Webb Telescope and although I'm not superstitious, I'll be tempted to cross my fingers when launch day finally comes. Enthalpy, thank you for your comments about the transparency of the atmosphere. Intriguingly, the Bortle Scale - or someone referring to it - did claim an upper naked-eye limit of +7 magnitude, albeit under 'exceptionable' viewing circumstances. If so, then I guess this degree of clarity would also apply to space itself.

In space, your visibility should be about the same as it is on a very clear night on the ground, but the stars wouldn't twinkle, a phenomena caused by atmospheric distortion. As Enthalpy posted above, newer telescopes, such as the twin Kek telescopes and the future TMT (Thirty Meter Telescope, first light scheduled for some time in 2022), have adaptive optics capability, with the ability to compensate for atmospheric distortions by adjusting the mirror with small motors.

 

- Arch