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The answer is that the two telescopes have different focal lengths and that focal length and mirror size are parameters that can be independently adjusted (there are obviously other tradeoffs to do with resolution and focal ratio). Here's a description of why. Here is a rather terrible diagram of a simplified Newtonian reflector – I've simplified it just by ...


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One point touched on but not expanded upon is high contrast imaging. That's less important when imaging a black hole or a nebula or galaxy because they don't change much and the image can be reconstructed. Imaging a planet orbiting next to or crossing over a star requires very high contrast and that wouldn't be possible with an airborne telescope, doubly ...


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The place to start is by listing the science objectives of the mission. Balloon telescopes can be much less expensive than satellite borne ones, but the design of a satellite borne one allows a much longer life span, zero gravity to distort the telescope, less infrared heating from the earth, a wider field of view, and I'm sure many more things. You would ...


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A couple more things to consider (that I haven't seen in the several existing answers) about having a James-Webb class observatory in the upper Earth atmosphere instead of at Sun-Earth L2: You've significantly degraded your available fields of view compared to Sun-Earth L2. Not only is your "below" completely occupied by Earth, but "above&...


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The JWST will be in a halo “orbit“ at the Earth-Moon L2 point, 930,000 miles from the Earth, and over four times as far away from us as the Moon is. It would need to be one impressive balloon to achieve that kind of altitude. And it has to be that far away so that its sunshade can deflect heat from both the Earth and Sun, which is necessary for an infrared ...


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Logistically speaking, it might be more complex than it sounds. The bit that initially stuck out to me is that the South Pole launch is planned for December 2023. December means summer - it is likely that the weather window during which it is practical to fly this mission is quite narrow, only a few months. Outside of that period, recovery becomes ...


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JWST is to be a 6.5-meter telescope, while ASTHROS is only 2.5 meters. That's a pretty big difference. On the other hand, perhaps you could spend half the cost of JWST and engineer a 6.5-meter balloon-hosted telescope, but I'm not sure.


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No, I don't believe so. The reason space telescopes do well is that there's no atmosphere limiting the optical performance of the device. A telescope on a balloon is not anywhere near above the atmosphere. It's above a lot of the water in the atmosphere, which is why IR things can be better there, but there is still turbulence above it which will limit ...


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