NNTT's Next Generation: Harmonizing a Quartet of Large Telescopes

By Thomsen, Dietrick E. | Science News, January 25, 1986 | Go to article overview

NNTT's Next Generation: Harmonizing a Quartet of Large Telescopes


Thomsen, Dietrick E., Science News


The National New Technology Telescope (NNTT) is the National Optical Astronomy Observatories' (NOAO's) entry in what may be the coming generation of large telescopes. The NNTT, a proposed multiple-mirror telescope, would employ four separate mirrors to act together to simulate a single mirror 15 meters across, or to act separately. At a recent meeting in Houston of the American Astronomical Society, the NNTT's planners announced significant developments in its design, and the director of the project, Jacques M. Beckers, described successful tests of a new method for making the mirrors act in concert.

The plan, as it has evolved since 1984 when NOAO decided that the NNTT should be a multiple-mirror telescope, envisions four mirrors, each of 7.5 meters diameter, hung in a common altitude-azimuth mounting. In this mounting the telescope rotates in horizontal and vertical planes. The more usual equatorial mounting, in which the telescope rotates vertically and in the plane of the celestial equator, makes it easier to follow stars across the sky. However, the telescope has to be hung at an angle to the vertical, and in the case of an arrangement as bulky as the NNTT, an equatorial mounting would impose torques and shears that the system couldn't sustain. As does the housing of the existing Multiple Mirror Telescope, the entire building housing the NNTT would rotate horizontally (telescopes usually rotate inside their buildings).

Each of the 7.5-meter mirrors would be bigger than any telescope mirror would be bigger than any telescope mirror now existing. Earlier concepts of the NNTT had generally foreseen a larger number of smaller mirrors, but recent progress in spin-casting of large mirrors, pioneered by Roger Angel of the University of Arizona in Tucson (SN: 2/16/85, p. 106), has made the larger mirrors seem practical.

Together the four mirrors would simulate a single mirror 15 meters across, for imaging purposes. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

NNTT's Next Generation: Harmonizing a Quartet of Large Telescopes
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Author Advanced search

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.