Page 51 - BBC Sky at Night - September 2017 UK

THE SKY GUIDE SEPTEMBER 51

NEED TO
KNOW

The terms and symbols
used in The Sky Guide
SATURDAY! 81,9(56$/!7,0(!"87#!
The Moon shows a good libration
9 Despite being under high illumination, AND BRITISH SUMMER
to favour the northwest limb.
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features such as 129km-wide crater
Pythagoras will be well positioned and can Universal Time (UT) is the
standard time used by
be followed as the evening terminator astronomers around the
approaches on 17 September.
world. British Summer
Time (BST) is one hour
ahead of UT.
5$!"5,*+7!$6&(16,21#!
$1'!'(&$!"'(&/,1$7,21#!
These coordinates are the
night sky’s equivalent of
longitude and latitude,
describing where an object
lies on the celestial ‘globe’.
FAMILY FRIENDLY
Objects marked with
this icon are perfect for
showing to children

NAKED EYE
Allow 20 minutes for
your eyes to become
SUNDAY! Mercury MONDAY! This TUESDAY! The linear dark-adapted
17 to the east of 18 crescent Moon is 19 alignment PHOTO OPPORTUNITY
appears
morning’s
planetary
4%-lit waning
20 arcminutes
Use a CCD, planetary
continues into
Mars this morning. Catch them 0.5º south of mag. +1.4 Regulus this morning with a really thin camera or standard DSLR
both around 90 minutes before (Alpha (_) Leonis). Mercury, 1.3%-lit waning crescent Moon, BINOCULARS
sunrise – that’s 05:20 BST Mars, the crescent Moon and just visible before sunrise. 10x50 recommended
(04:20 UT) from the centre Venus will also appear in a line.
of the UK. SMALL/
MEDIUM SCOPE
Reflector/SCT under 6 inches,
refractor under 4 inches
SUNDAY! The MONDAY X! LARGE SCOPE
24 Moon, low in 25 Schaumasse can inches, refractor over 4 inches
Mag. +12.7
Reflector/SCT over 6
20%-lit
comet 24P/
waxing crescent
be seen against
the southwest at 20:00 BST the northern region of the Beehive
(19:00 UT), shows a favourable Cluster, M44 in Cancer. Catch them
libration for the southeast limb. together in the early hours.
It also occults mag. +3.9
Gamma (a) Librae at 19:48 BST
(18:48 UT), reappearing at
20:55 BST (19:55 UT).
W WEDNESDAY! !)$0,/<!67$5*$=,1*!%!&' SEP GETTING STARTED
The
27 will be visible The Great Square of Pegasus is a large, prominent If you’re new to astronomy,
Lunar X
IN ASTRONOMY
pattern of stars, approximately square in shape. On a
moonless night, identify the pattern – its sides are about
at around
21:20 BST (20:20 UT). It’s 1.5 times the width of an adult’s fist at arm’s length – using our all- you’ll find two essential
fascinating to watch the letter sky-chart on page 54. Set the challenge to count the stars within its reads on our website. Visit
‘X’ form as the dawn terminator boundary. Young eyes should find it easier to pick out the fainter http://bit.ly/10_Lessons for
approaches the region, roughly stars. The total can be used to gauge your sky transparency. Not our 10-step guide to getting
one-third of the way up from including the corners, a count of 0-2 is poor, 3-7 average, 8-11 started and http://bit.ly/
the southern limb. good and 12 or more excellent. Conditions and totals may vary First_Tel for advice on
between nights. www.bbc.co.uk/cbeebies/shows/stargazing choosing a scope.

skyatnightmagazine.com 2017