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Comment: Only advantage is the light weight (Score 2, Interesting) 165

by helioquake (#23272404) Attached to: Proposed Telescope Focuses Light Without Mirror Or Lens
The article makes it sound like only a 30-meter "Fresnel" optics can allow to resolve an earth-size object within 30 light-years.

The fact is that any conventional 30-meter telescope can resolve an earth-size object within 30 light-years (circa 6000Angstrom in wavelength). Spatial resolution can be determined by the ratio of wavelength to diameter of the optics:

    6000A / 30m ~ 2e-8 radian ~ 0.004 arcsec.

So a 30m telescope can resolve an object in angular size of 0.004arcsec at 6000Angstrom.

At the distance of 30 light-years, the earth-size object looks like

    6400km / 30lyr ~ 2e-8 radian ~ 0.004 arcsec.

So that's that. This telescope doesn't give us any special resolving power per optics size. So the advantage is merely its light weight.

Since the precise alignment of holes is required for this optics to work, I can see why this project got kicked out by ESA. It's probably too premature to attempt in deploying this kind of precision engineering in space today.
Space

+ - NASA educator-astronaut Barbara Morgan to fly STS-

Submitted by
WaltonNews
WaltonNews writes "Barbara Radding Morgan is scheduled to fly on STS-118 aboard Space Shuttle Endeavour to the International Space Station on June 2007. A member of NASA's Teacher-in-Space program in 1985, Morgan has remained active in the U.S. space program. In January 1998, she was selected as the first NASA Educator Astronaut. For the complete story: http://www.itwire.com.au/content/view/8802/1066/."

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