How big can we make a telescope?

I've mentioned in earlier posts that it will be much cheaper to build immense space-based observatory instruments than to even come close to launching an interstellar expedition.

There are several figures of merit including total light gathering area and separation of light gathering points.

Imagine nanotechnology that "grows" a module from material in the asteroid belt, and then dispatches it out beyond the dust of the inner solar system. The technology can record the visible and infrared light waveforms in sufficient resolution to combine them from different modules and synthesize an image from a mirror the size of the separation. (This kind of recording delayed synthesis has long been a thing for radio frequency observation.)

How small of details on exoplanets could be seen? Is there a diminishing return when making the distributed modules ever bigger, or can resolution go up indefinitely?

Does the light gathering capacity matter as well? What is the right order of magnitude to match the magnification? Off hand, I expect the target to be lit as bright as daylight, just very tiny; does the total light gathered change with the apparent target size?

Today, a star-shield is needed to prevent a planet from being washed out from the nearby star. Would a narrow enough field of view make that simply unnecessary, or is there some optical effects related to absolute separation of the targets?

summary

1. How small of details on exoplanets could be seen? math: separation between modules, individual module size, and resolving power; resolving power to exoplanet distance and ground feature size.
2. Is there a diminishing return when making the distributed modules ever bigger, or can resolution go up indefinitely?
3. What is the relationship between light gathering capability, brightness of the image, and size of the imaged object?
4. Use with star shield?

posted over 8 years ago

JDługosz‭

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