Astronomy - USA (2020-03)

CONTENTS 60

4 ASTRONOMY • MARCH 2020

18

Hubble’s greatest hits

The world’s favorite orbiting

observatory has transformed

our knowledge about

exoplanet atmospheres, the

fate of the universe, and

almost everything in between.

RICHARD TALCOTT

30

How the Ritchey-Chrétien

telescope was born

George Ritchey had great

vision and skill. Henri

Chrétien was a brilliant

astronomer and optical

engineer. Together, they

created one of today’s best

telescope designs. RON VOLLER

36

Sky This Month

Venus sidles up to Uranus.

MARTIN RATCLIFFE AND

ALISTER LING

38

Star Dome and

Paths of the Planets

RICHARD TALCOTT;

ILLUSTRATIONS BY ROEN KELLY

44

Do all galaxies have

dark matter?

The discovery of two ghostly

galaxies created quite a

hullabaloo in the astronomical

community. But the jury’s still

out on what’s really going on.

JAKE PARKS

52

Secrets of the Northern

Pinwheel Galaxy

Think you know the big

spiral M101? Take a deep

dive into its myriad

details, and you’ll know

it like never before.

ROD POMMIER

56

Explore the Moon

at First Quarter

If you’re just starting out,

our natural satellite makes a

tempting target in the evening

sky. MICHAEL E. BAKICH

60

Run a Messier marathon

Seeing all 109 objects in

one night should be on

your observing bucket list.

MICHAEL E. BAKICH

68

Ask Astro

Weighing black holes.

IN EVERY ISSUE

From the Editor 5

Astro Letters 6

New Products 65

Reader Gallery 70

Advertiser Index 73

Breakthrough 74

FEATURES

MARCH 2020

VOL. 48, NO. 3

Astronomy (ISSN 0091-6358, USPS 531-350)

is published monthly by Kalmbach Media

Co., 21027 Crossroads Circle, P. O. Box 1612,

Waukesha, WI 53187–1612. Periodicals postage

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POSTMASTER: Send address changes to

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Go to http://www.Astronomy.com

for info on the biggest news and

observing events, stunning photos,

informative videos, and more.

ONLINE

FAVORITES

7

QUANTUM GRAVITY

Everything you need to

know about the universe

this month: the mystery

of Planet Nine, water

vapor on Europa, ancient

life in Australia, bright

X-ray bursts, and more.

COLUMNS

Strange Universe 14

BOB BERMAN

Secret Sky 16

STEPHEN JAMES O’MEARA

Binocular Universe 64

PHIL HARRINGTON

Observing Basics 66

GLENN CHAPLE

ON THE COVER

The Carina Nebula is the largest

and brightest Milky Way star-

forming region. Hubble captured

this image of its dusty pillars.

NASA/ESA/N. SMITH (UC, BERKELEY)/

THE HUBBLE HERITAGE TEAM (STSCI/AURA)

My Science

Shop

Perfect gifts for

your favorite

science geeks.

Trips and

Tours

Travel the

world with the

Astronomy staff.

Ask Astro

Archives

Answers to all

your cosmic

questions.

Globes

From Mercury

to Pluto, get the

hottest globes

around.

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