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Giant Telescopes Of The Future

Posted by timothy on from the letting-in-the-light dept.

mindpixel writes: "Mindjack just published my article about the the future of very large telescopes, such as the VLT and the OWL which I talked about in my /. interview. In addition, I talk about a future space-based telescope that would use the Sun's gravity to 'image large surface features,' of extrasolar planets, which telescpes like the VLT can just detect, 'such as oceans, continents or ice caps, or even the impact of civilization on such features.'"

4 of 136 comments (clear)

  1. Re:Borrrrrrrrring!!!!1! by PhuCknuT · · Score: 4, Insightful

    The solar foci telescope idea sounds really cool, but it's got a big limitation. It can only see in 1 direction. With a 450au orbit, its orbital period is around 9500 years. That means it will only move 0.037 degrees through it's orbit every year. And assuming it won't be carrying the fuel to make huge orbital adjustments, it will only be able to view along the plane of it's orbit. We would have to have a good dense area of sky to view before launching something like that. :)

  2. Solar foci telescpoe by PhuCknuT · · Score: 4, Insightful

    The solar foci telescope idea sounds really cool, but it's got a big limitation. It can only see in 1 direction. With a 450au orbit, its orbital period is around 9500 years. That means it will only move 0.037 degrees through it's orbit every year. And assuming it won't be carrying the fuel to make huge orbital adjustments, it will only be able to view along the plane of it's orbit. We would have to have a good dense area of sky to view before launching something like that. :)

    1. Re:Solar foci telescpoe by mindpixel · · Score: 3, Insightful

      Yes. Which is why you still need something large on the ground like OWL to do the initial target selections... which is ironic because that's the reverse of how the Hubble/VLT work together today.

      Today the Hubble acts as a finder scope and the VLT as a spectrometer. The Hubble's small mirror, and the fact that it is in space make it a poor spectrometer for distant or faint objects. The reason for this (other than the small primary) is that after about 20 minutes exposure in space, the CCD becomes saturated with cosmic rays. On the ground, the atmosphere filters the cosmics, allowing for much longer exposures than are possible in space.

  3. Re:Why not use Earth as the lens? by T-Punkt · · Score: 3, Insightful

    > What is the focal length for the earth anyway?

    No idea, but given that the earth is much lighter and thus much less "light bending" as the sun I guess it's much, much, much larger... (a few light years?)