Excerpt from Stargazer by Fred Watson, plus links to reviews, author biography & more

Summary |  Excerpt |  Reviews |  Beyond the Book |  Readalikes |  Genres & Themes |  Author Bio

Stargazer

The Life and Times of the Telescope

By Fred Watson

Stargazer
  • Critics' Opinion:

    Readers' Opinion:

     Not Yet Rated
  • Hardcover: Jul 2005,
    360 pages.
    Paperback: Jun 2006,
    352 pages.

    Publication Information

  • Rate this book


Book Reviewed by:
BookBrowse Review Team

Buy This Book

About this Book

Print Excerpt


Of course, optical telescopes also predate all the other types by more than 300 years. So perhaps it was not surprising that those attending our forum paid little more than lip-service to the newer, 'invisible' astronomies. There was a clear underlying message: at this meeting, optical astronomy ruled, OK. Wavelength chauvinism was alive and well in Munich.

Then there was the obsession with size. Just why do optical telescopes have to be so big?

Unlike Gary Larson's cartoon telescope, today's real telescopes have at their heart a shallow, concave mirror to collect and focus the incoming light. Bigger mirrors collect and concentrate more light, and an insatiable appetite for light—even in very small quantities—is the most common dietary complaint among astronomers. The more light that can be collected, the fainter the objects that can be studied.

But there is another craving that draws astronomers towards ever bigger telescope mirrors, one known as resolution—the fineness of the detail that can be seen in a magnified image of the sky. The quest for resolution is as old as the telescope itself, for it was the instrument's ability to reveal invisible detail that made it such an astonishing invention in the first place. Today, the physics of the situation is well understood: given the necessary degree of optical perfection, the bigger the telescope mirror the finer the detail it is capable of recording.

Like all dimensions in the sky, resolution is measured as an angle. It is expressed in arcseconds—microscopic units that are to angles what nanometres are to length. Geometry tells us that an arcsecond is 1/3600th of a degree. So much for geometry; it's much more instructive to imagine a person 5 kilometres away holding up a coin. An Australian dollar, a British pound and a US quarter are all about the right size. To your eye, the coin's diameter at that distance is one arcsecond—and you would need a sizeable telescope to be able to see it.

Putting some figures on resolution, a one-metre diameter telescope mirror is theoretically capable of showing detail on a scale of a little more than 0.1 arcseconds—the coin at 50 kilometres. But a 4 metre mirror could resolve detail of one-quarter the size—0.03 arcseconds. That is fine enough to detect surface markings on the planet Pluto, or the disc of the giant star Betelgeuse. Bigger is definitely better.

Unfortunately, there is a wholly unwelcome natural phenomenon that plays havoc with resolution, and that is atmospheric turbulence. We're all familiar with what happens when a jet aircraft ploughs into turbulent air 10 kilometres or so above the ground. The nerve-racking shaking and juddering happens even in cloudless skies. That same turbulence has an equally alarming effect on rays of light coming down through the atmosphere. It gives the stars their appealing twinkle when seen with the naked eye—but in the telescope, what should be infinitesimally small points of light are blown up into fuzzy, trembling balls.


Seeing the unseeable

What can be done about the problem of seeing? The direct approach is to take your telescope above the atmosphere, but that is very expensive. The Hubble Space Telescope, launched in 1990, was designed primarily with this in mind (though its high-level vantage point also provided unprecedented access to the ultraviolet waveband). The story of the Hubble, its flawed 2.4 metre mirror and the 1993 rescue mission that enabled engineers to recover most of its intrinsic resolution is well known, but less widely appreciated is its cost. The eventual bill to build, launch and fix it was well over US$2 billion (1990 dollars), and by the time the project is completed sometime beyond 2010, it will have notched up more than US$6 billion.

From Stargazer by Fred Watson, pages viii - x of the Prologue, and pages 1-17 of Chapter 1. Copyright Fred Watson. All rights reserved. Excerpt reproduced by permission of Da Capo Press.

Membership Advantages
  • Reviews
  • "Beyond the Book" backstories
  • Free books to read and review (US only)
  • Find books by time period, setting & theme
  • Read-alike suggestions by book and author
  • Book club discussions
  • and much more!
  • Just $10 for 3 months or $35 for a year
  • More about membership!
Member Benefits

Join Now!

Check the advantages!
Just $10 for 3 months or $35 for a year

    •  
    • FREE
    • MEMBER
    • Range of media reviews for each book
    • Excerpts of all featured books
    • Author bios, interviews and pronunciations
    • Browse by genre
    • Book club discussions
    • Book club advice and reading guides
    • BookBrowse reviews and "beyond the book" back-stories
    •  
    • Reviews of notable books ahead of publication
    •  
    • Free books to read and review (US Only)
    •  
    • Browse for the best books by time period, setting & theme
    •  
    • Read-alike suggestions for thousands of books and authors
    •  
    • 'My Reading List" to keep track of your books
    •  
Sign up, win books!

Editor's Choice

  • Book Jacket
    The Valley of Amazement
    by Amy Tan
    "Mirror, Mirror on the wall
    I am my mother after all!"


    In my pre-retirement days as a professor ...
  • Book Jacket: A Man Called Ove
    A Man Called Ove
    by Fredrik Backman
    Reading A Man Called Ove was like having Christmas arrive early. Set in Sweden, this debut novel is ...
  • Book Jacket
    The Search
    by Geoff Dyer
    All hail the independent publisher! In May 2014, Graywolf Press brought two of long-revered British ...

First Impressions

Members read and review books ahead
of publication. See what they think
in First Impressions!

Books that
expand your
horizons.

Visitors can view a lot of BookBrowse for free. Full access is for members only

Find out more.

Book Discussions
Book Jacket

Tomlinson Hill
by Chris Tomlinson

Published Jul. 2014

Join the discussion!

Win this book!
Win The Angel of Losses

The Angel of Losses

"Family saga, mystery, and myth intersect in Feldman's debut novel." - Booklist

Enter

Word Play

Solve this clue:

E C H A Silver L

and be entered to win..

Books thatinspire you.Handpicked.

Books you'll stay up all night reading; books that will whisk you to faraway places and times, books that will expand your mind and inspire you -- the kinds of books you just can't wait to tell your friends about.