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
  • First Published:
    Jul 2005, 360 pages
    Paperback:
    Jun 2006, 352 pages

  • 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!

Support BookBrowse

Become a Member
and discover your next great read!

Join Today!

Book Discussion
Book Jacket
The Opposite of Everyone
by Joshilyn Jackson

"Quirky and appealing characters, an engaging story, and honest dialogue make this a great book!"
- BookBrowse

About the book
Join the discussion!

Editor's Choice

  • Book Jacket
    In the Country of Men
    by Hisham Matar
    Labeled by some as the "Libyan Kite Runner", In The Country of Men does share some ...
  • Book Jacket: Holding Up the Universe
    Holding Up the Universe
    by Jennifer Niven
    Jennifer Niven's spectacular Holding Up the Universe has everything that I love about Young ...
  • Book Jacket: Coffin Road
    Coffin Road
    by Peter May
    From its richly atmospheric opening to its dramatic conclusion, Peter May's Coffin Road is a ...

First Impressions

  • Book Jacket

    Victoria
    by Daisy Goodwin

    Daisy Goodwin breathes new life into Victoria's story, and does so with sensitivity, verve, and wit." - Amanda Foreman

    Read Member Reviews

Win this book!
Win All the Gallant Men

All The Gallant Men

The first memoir by a USS Arizona survivor, 75 years after Pearl Harbor.

Enter

Word Play

Solve this clue:

K Y Eyes P

and be entered to win..

Books that     
entertain,
     engage

 & enlighten

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

Join Today!

Your guide toexceptional          books

BookBrowse seeks out and recommends books that we believe to be best in class. Books that will whisk you to faraway places and times, that will expand your mind and challenge you -- the kinds of books you just can't wait to tell your friends about.

 
X

Free Weekly Newsletter

Keep up with what's happening in the world of books:
Reviews, previews, interviews and more!



Spam Free: Your email is never shared with anyone; opt out any time.