JUNE 2020 OBSERVING
Deep-Sky Wonders by Sue French
The First
Plowman
Boötes is home to one
globular cluster and many
great galaxies.T
he name Boötes is often said to
come from a Greek term meaning
“ox driver.” According to some tales,
Boötes invented the ox-drawn plow to
make the cultivation of crops easier.
Proud of her son’s creation, the god-
dess Ceres had Boötes placed among the
stars. We can also see his creation in the
nearby asterism of the Big Dipper, which
is called the Plough in the British Isles.
Have you ever wondered how to pro-
nounce Boötes? One accepted pronun-
ciation is bo-OH-teez. For an expanded
guide to the constellations and their
pronunciations, visit https://is.gd/
constellations.54 JUNE 2020 • SKY & TELESCOPE
To celebrate 20 years of Sue French’s
stellar contributions to Sky & Tele-
scope, we will be sharing the best of
her columns in the coming months.
We have updated values to current
measurements when appropriate.We’ll begin at Delta (δ) Boötis, a
spacious double star whose components
are widely parted by my 105-mm (4.1-
inch) refractor at 17×. The deep-yellow
primary is a giant star with a spectral
type of G8, and the pale-yellow star fol-
lowing it across the sky is similar to our
Sun. Despite the gulf between them,
these stars form a true pair about 122
light-years away from us. Their angular
separation on the sky tells us that they
must be separated in space by at least 10
times the average Sun-Pluto distance.
Canadian amateur Dave Johns told
me about a cute asterism he found 3.1°
west of Delta. His Kangaroo spans
1.7° from nose to tail and makes a nice
target for big binoculars or a small,
wide-fi eld telescope. My 18×50 image-
stabilized binoculars show enough stars
to see his shape, with the Kangaroo
boinging his way east. My 105-mm
scope at 17× nicely displays the 21 stars
(magnitudes 7 to 11) that make up his
outline. The Kangaroo’s brightest star
joins his foreleg to his body and shines
with a golden hue.
Our next stop is the lovely double
star Epsilon (ε) Boötis. It’s commonly
known as Izar, an Arabic word mean-
ing girdle or loincloth, denoting the
star’s position in its constellation fi gure.
William Herschel discovered the pair
in 1779, describing it as “a very beauti-
ful object.” He called the brighter star
“reddish” and the fainter one “blue, or
rather a faint lilac.” Friedrich Georg
Wilhelm von Struve bestowed the name
Pulcherrima (Most Beautiful) on this
double, calling its stars “very yellow”
and “very blue.”5529UGC
92425714Kangarooβδεγλρσ11BOÖTESIzar5371538353955557HD 12535138546615 h 00 m+45°14 h 30 m 14 h 00 m+40°+35°+30°Star magnitudes
3 654 78And next Boötes comes, whose order’d Beams
Present a Figure driving on his Teams.
— Marcus Manilius, Astronomica