Spaceship based telescopes

[Anthony]

Originally Posted by David L Pulver

* However, various sources and HIGH TECH's suggestion for Telescopic Vision implies that a Hubble or KH-11 style system is closer to 4,000 to 8000x. That would be 160, 000 to 640,000 lbs.

Diffraction-limited optics have a resolution of (wavelength) * 1.22 / (diameter), meaning you need a minimum lens diameter of (wavelength)*1.22/(resolution). Human 20:20 vision is defined as 1 minute of arc resolution (1/3438 radians) at a wavelength of 400-700 nm, so for 1x you need (700 nm) * (3438) * (1.22) = ~2.9mm optics. Most good telescopes are diffraction-limited, so the Hubble has about 800x human visual resolution.

You can, of course, magnify by more than 800x; it will just be a bit blurry. Also, the diffraction limit is the size of the blurry spot a point-like object becomes; if you know you're looking at point-like objects (which will often be true in astronomy) you can do a bit more processing to find the center of the blurry spot, and maybe even figure out that two blurry spots are overlapping. This will not typically be very useful outside of astronomy.

Originally Posted by David L Pulver

So, which is wrong:
(a) "scale by the square of magnification"

Really, 'scale lens diameter by magnification. This tends to result in an actual scaling factor between 2 and 3, as a larger lens requires more support.

Originally Posted by David L Pulver

(b) the estimate that Hubble / KH-11 is about 4,000 to 8,000x magnification

This one is wrong (well, it might magnify by that much to make the images easier to work with, but it doesn't have that much resolution).

Originally Posted by David L Pulver

(c) the base weight of the 10x system.

Binoculars are not a good model for sensors, as they're limited by the structure of your eye. Also, field of view matters, a telescope with a 1 degree field of view is a lot less weight than a wide angle lens.

Originally Posted by David L Pulver

Also, it looks like if you scale DOWN you get a super-light 1x magnification system. At TL8 what would be a realistic weight for a 1x "human eyeball" camera?

The equivalent of human visual resolution in a 60 degree arc (the human eye only has that resolution in about a three degree arc, but cameras cannot easily emulate that) is about 13 megapixels, so your average cell phone camera is slightly worse than human eyeball.