The Cambridge Double Star Atlas

156 Pages·2009·15.56 MB·English

by  James Mullaney

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The Cambridge Double Star Atlas
This magnificent atlas contains the most attractive
andinterestingdoubleandmultiplestarsfor viewing
with binoculars and telescopes. It is a must have for
stargazers who want to explore these fascinating
objects.
The first modern star atlas devoted to double and
multiple stars, it plots nearly 2,400 selected pairs,
each labeled with discoverer, catalog, and/or
observatory designations. A superb introduction to
this important class of celestial objects, it is spiral
bound and printed in red light friendly colors,
making it ideal for use in the field.
Written by experienced observer James Mullaney,
and beautifully illustrated by renowned celestial
cartographer Wil Tirion, this atlas provides an
easy to use“celestialroadmap”tolocateandidentify
double and multiple stars. Other deep sky objects
such as star clusters, nebulae, and galaxies are also
included, and are color coded for easy recognition
and identification, making this an all purpose
observing reference.
james mullaney, former assistant editor at
Sky & Telescope magazine, is an astronomy writer,
lecturer, and consultant, who has published more
than 500 articles and seven books on observing the
wonders of the heavens.
wil tirion is a full time uranographer. He is
famous for the numerous star charts he has created
for astronomy books, atlases, and magazines.

THE CAMBRIDGE
DOUBLE
STAR ATLAS
JAMES MULLANEY, FRAS
WIL TIRION
CAMBRIDGE UNIVERSITY PRESS
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo
Cambridge University Press
The Edinburgh Building, Cambridge CB2 8RU, UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Information on this title: www.cambridge.org/9780521493437
© J. Mullaney and W. Tirion 2009
This publication is in copyright. Subject to statutory exception and to the
provision of relevant collective licensing agreements, no reproduction of any part
may take place without the written permission of Cambridge University Press.
First published in print format 2009
ISBN-13 978-0-511-50847-9 eBook (NetLibrary)
ISBN-13 978-0-521-49343-7 paperback
Cambridge University Press has no responsibility for the persistence or accuracy
of urls for external or third-party internet websites referred to in this publication,
and does not guarantee that any content on such websites is, or will remain,
accurate or appropriate.
CONTENTS
Introduction page 1
Map parameters and selection criteria 1
Discoverer/catalog/observatory designations 2
Observer, atmosphere and instrument 5
Double and multiple star showpieces 10
Some recommended references 22
About the authors 23
Acknowledgements 24
Star charts 25
Appendix A: Constellation table 89
Appendix B: Table of Greek letters 92
Appendix C: Cambridge Double Star Atlas
target list 93

INTRODUCTION
We are very pleased to present what is the first as the world’s greatest celestial “cartographer” and
major modern star atlas devoted primarily to the creator of such classic works as the magnificent
observation of visual double and multiple stars. SkyAtlas2000.0.Theydesignatenearly2,400double
With the widespread growing popularity of viewing and multiple stars suitable for viewing with typical
these tinted jewels of the heavens by amateur “backyard” telescopes in the 2 inch to 14 inch
astronomers today, the need for such a work clearly aperture range. These are shown using the standard
exists. The one classic atlas that identified these symbol of a star bisected by a bar and are labeled in
objects, along with their discoverers and/or catalog green, which shows up well under the red lighting
designations, was Norton’s Star Atlas through its first used at the telescope to maintain dark adaptation
17 editions. Sadly, all later revised and redrawn (see below). In addition to writing this introductory
versions of this atlas – initially re titled Norton’s guide to the Atlas, I selected the original target list
2000.0 and currently back to the original Norton’s itself (as well as the showpiece roster below) based
StarAtlas–droppedthediscovererandcataloglabels on my personal observations of tens of thousands
(along with those of the clusters, nebulae and of pairs over the past 50 years using literally
galaxies discovered by the Herschels) to the dismay hundreds of telescopes of all types and sizes
of observers of both classes of deep sky wonders. within the aperture range stated above. No doubt,
It is now estimated that at least 80 percent of the experiencedobservers willhavefavoritesthat arenot
stellar population exists as pairs or multiple systems plotted/designated as being multiple stars. If every
of suns. Their amazing profusion, combined with objectthatisvisuallydoubleinsomesizeoftelescope
a seemingly endless variety of color combinations, were to be indicated, fully half of all the stars
brightnesses, separations, and component plotted on the maps would have bars through them!
configurations, make them fascinating objects for But those shown certainly are among the most
both leisurely viewing and serious study. Abounding attractive and interesting in the sky, and as such
as they do among the naked eye stars, literally offer a well rounded selection for surveying these
thousands of them are visible with even the smallest fascinating stellar combos. (See Appendix C for
of glasses (and, in the case of the wider pairs, with the complete target list of pairs used in creating
binoculars as well) and on all but the very worst of this Atlas.)
nights – including those with bright moonlight, All told, some 25,000 stars are plotted in half
hazeandheavylightpollution.Sonotonlyarethese magnitude steps on the maps to a nominal visual
stars plentiful and easily located, but they are truly magnitude limit of 7.5 (the primary star’s brightness
ever fascinating sights! combinedwiththatofitscompanion/s,thecutofffor
While this new atlas was primarily designed thelatterbeingroughlymagnitude10.5),inaddition
with double star observation in mind, it also serves to 900 non stellar deep sky wonders. Angular
as a general purpose guide for viewing all types of separations range from those of tight challenging
deep skyobjects,showingasitdoesmanyprominent binaries reaching at least 0.5 arcseconds in their
asterisms, star clusters, nebulae, galaxies, variable orbits such as g Virginis and z Herculis out to ones
stars, and the majestic Milky Way itself. wide enough to be resolved with the unaided eye –
ones like the well known combos a Capricorni,
Map parameters and selection criteria
eLyraeandyTauri.Pairswiderthan180arcseconds
The 30 maps comprising the Atlas were planned, whose companionslie at or abovethe 7.5magnitude
drawn,andlabeledbyWilTirion,widelyrecognized limit are plotted as separate stars on the maps.
1
The CambridgeDouble Star Atlas
(These objects are typically excellent targets for Discoverer/catalog/observatory
viewing with binoculars.) designations
A number of doublesthat lie somewhat below the Presented below is a list of all the designations
Atlas limit are also plotted because they have used to identify the double and multiple stars
especiallystrikingcolorcontrasts,and/orcomponent plotted on the Atlas in addition to their proper or
configurations, as well as lying in or near striking common names (if any), and Bayer (Greek) letter
backgrounds such as that of a cluster or nebula. or Flamsteed number. There are several important
Inaddition,averyfewevenfainterpairsareincluded things to note in this regard. First, in some cases
for reasons other than their visual attractiveness – there may be a difference between a discoverer’s
famous ones like Winnecke 4, notable as actually original designation and an official catalog
beingMessier40,andKrueger60,areddwarfbinary designation. As one example, the striking triple
flare star. And while mentioning dim objects below systembMonocerotisiswidelyknownas“Herschel’s
our limit, it’s very important to point out here that Wonder Star” after Sir William Herschel who
many of the double and multiple stars plotted often discovered it. But its designation (in addition to its
have one or more fainter pairs lying within the same Greek letter/constellation) shown in all listings is
low-power eyepiece field! Thus, observers should S 919, signifying that it is the 919th entry in the
always check the field of view for these unsuspected great double star observer Wilhelm Struve’s
but fascinating duos in addition to scrutinizing the monumental catalog containing both his and other’s
primary target object itself. discoveries. Another case is the magnificent radiant
A magnitude scale and color coded key to the binary a Geminorum, or Castor. First discovered
symbols used to denote various types of deep sky by G.D. Cassini and later re discovered by
objects appears at the top of each map. Note that J. Bradley, it appears as S 1110 in double star lists,
the edges of the maps have green arrowed numbers again in addition to its Greek letter/constellation.
indicating adjoining maps (with some overlap) A third example involves one of the very first
in each direction, which will be very helpful in telescopic double stars ever noticed – the striking
navigating the Atlas. Also, blue solid lines have identicaltwinsunsofgArietis.Thisdoublestar was
been used to connect the principal stars in each found accidentally by Robert Hooke in 1664 while
constellation, the boundaries of which are indicated followingacometbutcarriesnodesignationbyhim,
by dashed lavender lines. These so called “stick being officially labeled S 180. (The preponderance
figures” also help you find your way around the sky. of various Struve designations for many of the
Many observers today use computerized (“Go To”) objects plotted on the Atlas maps is a result of the
target acquisition, and at least some of the brighter famed Struve dynasty of early double star observers,
doubles plotted – particularly those given in the who dominated that field, as did the Herschels in
showpiece roster below – can be so located by the discovery of clusters and nebulae.) The policy
entering their designation, common name and/or followedinthiscurrentworkistousethedesignation
coordinates on the controller’s keypad. (See by which each pair is officially and/or best known
Appendix C for a complete list of all pairs plotted.) by double star observers.
While these systems typically contain thousands There’s also the matter of multiple designations
of traditional deep sky objects, double and multiple for the same double star, some of which are shown
stars have largely been given short shift by the onthemapsandothersofwhicharenot.Inthefirst
programmers of their databases. And to many of us case, an observer may have originally discovered the
“purists,” this modern technology takes away much obviousduplicity ofanobjectwhileanother(typically
of the fun of good old fashioned “star hopping” to later) observer may have found an additional
learn and find your way around the sky – which is companion (usually a less obvious, closer in or
really one of the primary purposes of a star atlas dimmer one). These cases are shown as a dual
like this one. designation with a slash between them – such as
2