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Gallery: The Seven Most Incredible Telescopes In Existence

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    #2
    ps200306
    Registered Users Posts: 1,601 ✭✭✭ps200306


    Dr Silly Bollox MD wrote: »
    http://www.popsci.com/technology/gallery/2013-03/gallery-telescope-dishes

    Bit of an idiosyncratic choice. I'm not sure I'd have chosen many of those, except the VLT, and even there the article was about one instrument -- the amazing new spectrograph.

    There was an article recently (will try to dig it up) that ranked telescopes in terms of their contribution to science. You would have to include the SDSS 2.5m telescope at Apache Point observatory in New Mexico. It has been mapping the sky for the past 13 years with all the data available online to scientists and the public.

    apo_surveytelescope.jpg


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    #3
    Tea drinker
    Registered Users Posts: 2,817 ✭✭✭Tea drinker


    Weird, my scope isn't listed ?


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    #4
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 91,409 Mod ✭✭✭✭Capt'n Midnight


    If you want incredible how about the Large Zenith Telescope.

    6m parabolic liquid mirror.

    No grinding or polishing or all that other difficult manufacturing needed.

    only downside is you can only look straight up, which is fine if you are doing surveys or want the ultimate light bucket.


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    #5
    Tea drinker
    Registered Users Posts: 2,817 ✭✭✭Tea drinker


    ^ Interesting - Would be fascinating if we could manipulate a magnetic fluid to the necessary precision. Notice the guys are wearing masks when working with the mercury mirror
    http://www.youtube.com/watch?v=OJ6uIicHmmo


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    #6
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 91,409 Mod ✭✭✭✭Capt'n Midnight


    Tea drinker wrote: »
    ^ Interesting - Would be fascinating if we could manipulate a magnetic fluid to the necessary precision. Notice the guys are wearing masks when working with the mercury mirror
    http://www.youtube.com/watch?v=OJ6uIicHmmo
    you could possibly use gallium

    or put the whole thing in a sealed unit - then you can use cheap stuff like NaK - mixture of sodium and potassium , actually could that work under a thin layer of oil ??


    Magnets won't work.
    Or at least I can't figure out how you can them to balance out gravity evenly over the entire surface , and remember it's the spinning that gives the precise parabolic shape


    you could cheat and use a very flat mirror to reflect the light from off axis
    AFAIK the focal plane is still the same distance vertically from the mirror, but not sure of the distortions - can you simply cancel them out with a second mirror ?

    flat mirrors are easy - look at semiconductor industry
    https://en.wikipedia.org/wiki/Chemical-mechanical_planarization
    Typical depth-of-field requirements are down to Angstrom levels for the latest 22 nm technology.
    Hubble was only polished to 100 Angstrom.


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