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0 pointsmaxnoe12d ago0 comments

Our telescopes actually need the (or at least an) atmosphere to function.

There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.

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ultratalk12d ago

> Our telescopes actually need the (or at least an) atmosphere to function.

What about Hubble, Chandra, Spitzer, JWST, etc? As of my understanding, the only reason we haven't built radio and and other long-wave telescopes in space is because of their impractical size preventing them from being deployed in orbit.

> There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.

Examples?

voidUpdate12d ago

I believe we haven't built radio telescopes in space because we don't need to, and building them in space would be a lot more expensive.

https://commons.wikimedia.org/wiki/File:Atmospheric_electrom...

This shows that wavelengths between ~10cm and ~10m are largely unaffected by the atmosphere, so you wouldn't gain much from putting receivers of those wavelengths in space. Spitzer and JWST (IR), and Chandra (x-ray) operate in bands that are generally blocked by the atmosphere, and Hubble gets better images than a similarly sized earth-based telescope because of the atmospheric distortion (stars don't "twinkle" when you're in space), however there are still earth-based visible light telescopes because you can more easily build a massive one on earth than in space

BenjiWiebe12d ago

What? The atmosphere gets in the way. Ever heard of an (amateur/)astronomer talking about 'good seeing'? That's when the atmosphere is hindering you less than usual.

The limiting factor of passive optical telescopes on earth is the atmosphere.

SiempreViernes12d ago

They are talking about very high energy gamma-ray telescopes, the Imaging Cherenkov Telescopes.

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