Sky and Telescope - October 2016 - 2

October 2016
The New Horizons
spacecraft found
a vast plain and
Rockies-high mountains on Pluto. The
world might still be
active today.
PHOTO: NASA / JHUAPL / SWRI

O B S E RV I N G O C T O B E R

41 In This Section
42 October's Sky at a Glance
43 Binocular Highlight
By Mathew Wedel

44 Planetary Almanac

F E AT U R E S

14
COVER
STORY

New Horizons I:
Pluto's Amazing Story
This distant world bristles with geologic
diversity unmatched in the outer solar
system. By J. Kelly Beatty

Looking for Life on Mars
The ﬁrst phase of the ExoMars mission
arrives at the Red Planet this month to
search for evidence of past or present life.
By Camille M. Carlisle

What Caused the Great Eruption?
New theories and observations are helping
astronomers solve the mystery of Eta
Carinae's 19th-century explosion.
By Keith Cooper

The Backyard Sky: Fall
Say goodbye to summer with these
seasonal sights. By Rod Mollise

45 Northern Hemisphere's Sky
By Fred Schaaf

46 Sun, Moon & Planets
By Fred Schaaf

48 Celestial Calendar
By Alan MacRobert

52 Exploring the Moon

George Willis Ritchey's
Great Adventure
The world's giant telescopes today owe
their optical design to a star-crossed,
obsessive genius. By Ted Raﬀerty

54 Deep-Sky Wonders
By Sue French

HVAR OBSERVATORY

There's more to find online @

SkyandTelescope.com

S &T T E S T R E P O R T

58 Atik Inﬁnity Video
Astronomy Camera
By Rod Mollise
ALSO IN THIS ISSUE

By Peter Tyson

OBSERVING GUIDES

Our how-to guides will help you
get the most out of observing
classic celestial sights.
SkyandTelescope.com/objects
EQUIPMENT GUIDES

6 Letters

Find advice on choosing the
best tools for your adventures.

8 75, 50 & 25 Years Ago

SkyandTelescope.com/
equipment/basics

By Roger W. Sinnott

10 News Notes

ONLINE STORE

72 Astronomer's Workbench

Shop our online store for Moon
globes, sky atlases, and more.

By Jerry Oltion

74 Gallery

By Charles A. Wood

4 Spectrum
66

ESO / IDA / DANISH 1.5-M / R. GENDLER, J-E. OVALDSEN, C. THÖNE & C. FERON

On the cover:

VOL. 132, NO. 4

84 Focal Point
By Mark Mathosian

ShopatSky.com
TIPS FOR BEGINNERS

Here's everything you need to
get started in astronomy.
SkyandTelescope.com/letsgo

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October 2016 sky & telescope

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Sky and Telescope - October 2016

Table of Contents for the Digital Edition of Sky and Telescope - October 2016