Sky & Telescope - April 2021 - 2

CONTENTS

THE ESSENTIAL GUIDE TO ASTRONOMY

April 2021

VOL. 141, NO. 4

FEATURES

Cover Story:
12 How Well Do We Know
the Sun?
Even though the Sun is our nearest
star, we may not understand it as
well as we thought.
By Colin Stuart

A compact collection of galaxies
warrants not only observing but
also sketching.
By Howard James Banich

24 Resurrecting a Classic
Refractor
It took an astronomer who refused
to give up on herself to save a
historic observatory for a new
generation.
By M. Nicole Nazzaro

34 The Mystery of the
Martian Moons
Planetary scientists may soon
discover how the Red Planet
acquired its two potato-shaped
companions.
By Javier Barbuzano

62 Choosing an Astrograph
Here's a clever way to compare
features in deep-sky imaging scopes
before making a purchase.
By Oleg Bouevitch

ON THE COVER

62
OBSERVING
41

April's Sky at a Glance
By Diana Hannikainen

42

Lunar Almanac & Sky Chart

43

Binocular Highlight
By Mathew Wedel

PHOTO: N ASA / SDO

2

30

Orion's StarShoot G16
Deep Space Camera
By Johnny Horne

4

Spectrum
By Peter Tyson

44

Planetary Almanac

6

From Our Readers

45

Evenings with the Stars
By Fred Schaaf

7 75, 50 & 25 Years Ago
By Roger W. Sinnott

46

Sun, Moon & Planets
By Gary Seronik

8

48

Celestial Calendar
By Bob King

52

Exploring the Solar System
By Charles Wood

COLUMNS / DEPARTMENTS

54

58

First Exposure
By Ron Brecher
Going Deep
By Al Lamperti & Frank Colosimo

News Notes

57

Book Review
By M. Nicole Nazzaro

68

New Product Showcase

70 Astronomer's Workbench
By Jerry Oltion
72

Gallery

84

Focal Point
By Martin Hajovsky

ONLINE

SKY AT A GLANCE
Our popular column highlights celestial delights for the upcoming week,
complete with simple star maps and
observing tips.
skyandtelescope.org/ataglance
Extreme UV image
of the Sun, taken on
October 8, 2014

S&T TEST REPORT

ASTROPHOTO GALLERY
Enjoy readers' best images and
upload your own to share with your
fellow enthusiasts. Be sure to check
out the Editor's Choice winners.
skyandtelescope.org/gallery

ONLINE STORE
Equip yourself for astronomy excellence with webinars, sky atlases,
and more staff-selected products.
shopatsky.com

SKY & TELESCOPE (ISSN 0037-6604) is published monthly by AAS Sky Publishing, LLC, owned by the American Astronomical Society, 1667 K Street NW, Suite 800, Washington, DC
20006, USA. Phone: 800-253-0245 (customer service/subscriptions), 617-500-6793 (all other calls). Website: skyandtelescope.org. Store website: shopatsky.com. ©2021 AAS Sky
Publishing, LLC. All rights reserved. Periodicals postage paid at Washington, DC, and at additional mailing offices. Canada Post Publications Mail sales agreement #40029823. Canadian
return address: 2744 Edna St., Windsor, ON, Canada N8Y 1V2. Canadian GST Reg. #R128921855. POSTMASTER: Send address changes to Sky & Telescope, PO Box 420235, Palm
Coast, FL 32142-0235. Printed in the USA. Sky & Telescope maintains a strict policy of editorial independence from the AAS and its research publications in reporting on astronomy.

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18 The Lion's Galaxy Triplet


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Sky & Telescope - April 2021

Table of Contents for the Digital Edition of Sky & Telescope - April 2021

Contents
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Sky & Telescope - April 2021 - 1
Sky & Telescope - April 2021 - Contents
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