2021-01-16 New Scientist

52 | New Scientist | 16 January 2021

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JEF

F^ D

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/^ S

CIE

NC

E^ P

HO

TO

LIB

RA

RY

SIRIUS

These articles are

posted each week at

newscientist.com/maker

Abigail Beall is a science writer

in Leeds, UK. She is the author

of The Art of Urban Astronomy

@abbybeall

What you need

Clear night skies

Binoculars (optional)

A telescope (optional)

BETWEEN December and March,

there is something special for

stargazers in most of the world to

watch out for. You will be able to

see a pattern of stars, or asterism,

made up of six bright stars. It is

called the Winter Hexagon or

Winter Circle in the northern

hemisphere, or the Summer

Hexagon or Summer Circle

in the southern hemisphere.

Each of these stars is the

brightest in their constellation.

The asterism can be seen from

anywhere except the most

southern parts of New Zealand,

Chile and Argentina and further

south. Depending on where you

are in the world, its orientation

with the horizon will change, but

the pattern of the stars with respect

to each other will stay the same.

In previous columns, I have

revealed how to find Orion and its

brightest star, Rigel. Rigel makes

one corner of the hexagon. You

can find the hexagon’s next two

stars by extending Orion’s belt. In

one direction, you will find Sirius,

the brightest star in the night sky.

It will be low in the horizon in the

northern hemisphere and higher

in the southern hemisphere.

Go in the other direction, and you

will get to a bright star in Taurus

called Aldebaran, the next point.

To find the other stars in

the asterism, start by looking

for Pollux, in the constellation

Gemini. Draw a line from Rigel,

through Orion’s Belt and keep

going, past the red bright star

Betelgeuse and on until you see

two bright stars close together.

These are Castor and Pollux,

Six bright stars make a special hexagon in the night sky from

now until March. Abigail Beall reveals how to spot them

Stargazing at home

Hunting the Hexagon

the twin stars in Gemini. The

brightest of these, Pollux, is

another point on the hexagon.

It should be easy to fill in the

gaps where the remaining two

corners of the hexagon lie. If you

look between Sirius and Pollux

you will see a bright star, called

Procyon,in the constellation

Canis Minor. Follow the lines

of the hexagon round to look for

a star shining brightly opposite

where Sirius sits. This is the final

star in the hexagon, Capella, in

the constellation of Auriga.

In the southern hemisphere,

you can extend this asterism

to include another star, called

Canopus. This star is in the

constellation Carina. It is the

second brightest star in the night

sky after Sirius, and you can find it

by drawing a line from Canopus

to Sirius then continuing it until

you see a bright star.

Now we have them all: starting

from Rigel and going clockwise,

the hexagon’s stars are Sirius,

Procyon, Pollux, Capella and

Aldebaran. There are different

ways to remember their names,

but I think of it as the RSPPCA, the

Royal Society for the Protection of

People who Care about Asterisms.

If you find the two stars beginning

with P hard to recall, remember

Procyon is in Canis Minor and

Sirius is in Canis Major, and

the two dog constellations are

loyally next to each other. ❚

Feedback

Reading backwards

or forwards: the week

in weird p56

Tom Gauld for 

New Scientist

A cartoonist’s take

on the world p55

Almost the last word

How long is the gap

between the past

and the future? p54

Puzzles

Try our crossword,

quick quiz and

logic puzzle p53

Twisteddoodles

for New Scientist

Picturing the lighter

side of life p56

Stargazing at home

appears every four weeks

Next week

Science of cooking

RIGEL

ALDEBARAN

CAPELLA

POLLUX

PROCYON

Journey to the stars

Abigail Beall is accompanying

a New Scientist Discovery

Tour to Chile, the world

capital of astronomy

in November 2021.

For more details visit

newscientist.com/tours

Discovery Tours