VOL. 121, NO. 2€¦ · 60 Deep-Sky Wonders By Sue French S&T TEST REPORT 52 Celestron’s...

4 February 2011 sky & telescope

FEATURES

22 New Scrutiny of the Sun’s Secrets The Solar Dynamics Observatory is taking continuous, fi ne-scale movies of every layer from the Sun’s surface up. By Monica Bobra

28 The Perfect Solar Superstorm Solar storms in 1859 wreaked havoc on telegraph networks worldwide and produced auroras nearly to the equator. What would a recurrence do to our modern technological world? By Daniel N. Baker & James L. Green

36 Great Winter Double Stars This season is as notable for its doubles, triples, and quadruples as for its nebulae and star clusters. By James Mullaney

66 Solar Radio Astronomy It’s relatively easy to observe the Sun at radio frequencies. By J. Kelly Smith, David L. Smith, & William L. Joyner

72 Catch the Nearest Star The Sun provides astro- photographers with a captivating target every clear day. By Greg Piepol

THIS MONTH’S SK Y

40 Northern Hemisphere’s Sky By Fred Schaaf

43 February’s Sky at a Glance

45 Binocular Highlight By Gary Seronik

46 Planetary Almanac

48 Sun, Moon, and Planets By Fred Schaaf

50 Exploring the Moon By Charles A. Wood

57 Celestial Calendar By Alan MacRobert

60 Deep-Sky Wonders By Sue French

S&T TES T REPORT

52 Celestron’s 14-inch EdgeHD A 21st-century update transforms Celestron’s legendary telescope. By Dennis di Cicco

54 Quick Look: “Double-Stacked” P.S.T. By Sean Walker

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COVERSTORY

ALSO IN THIS ISSUE

6 Spectrum By Robert Naeye

8 Letters

10 50 & 25 Years Ago By Leif J. Robinson

14 News Notes

38 New Product Showcase

64 Telescope Workshop By Gary Seronik

76 Gallery

86 Focal Point By Chris Miller

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SKY & TELESCOPE (ISSN 0037-6604) is published monthly by Sky & Telescope Media, LLC, 90 Sherman St., Cambridge, MA 02140-3264, USA. Phone: 800-253-0245 (customer service/subscriptions), 888-253-0230 (product orders), 617-864-7360 (all other calls). Fax: 617-864-6117. Website: SkyandTelescope.com. © 2011 Sky & Telescope Media, LLC. All rights reserved. Periodicals postage paid at Boston, Massachusetts, and at additional mailing offi ces. 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 171, Winterset, IA 50273. Printed in the USA.

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On the cover: This not-to-scale composite of 2 SOHO images from diff erent instruments shows a coronal mass ejection blasting outward.

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February 2011VOL. 121, NO. 2

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