4 AUSTRALIAN SKY & TELESCOPE July 2019
REGULARS
5 Spectrum
6 Newsnotes
13 Discoveries
21 Newproductshowcase
FEATURES
14 Constantcontroversy
Astronomerscan’tagreeonthe
valueoftheHubbleconstant— the
numberthatdescribestheexpansion
rateoftheuniverse.A solutionis
nowhereinsight.
ByGovertSchilling
22 ThescienceofApollo
Rocksbroughtbackbytheastronauts
revolutionisedourunderstandingof
theMoon.
ByJohnA.Wood
28 ParkesandtheApollo 11
moonwalk
Australia’sveryown‘dish’played
a vitalroleinbringingthefirst
footstepsonanotherworldto
televisionscreensaroundtheglobe.
ByPeterRobertson
36 Lightinga cosmicfuse
TypeIa supernovae— thecosmic
milepoststhathelpedprovethe
universeis accelerating— arenot
asuniformasastronomersonce
thoughttheywere.
ByShannonHall
56 The allure of Betelgeuse
Astronomers are itching to know
when this red supergiant will go
supernova, but a clear answer eludes
them.
By Peter Tyson
Contents
July 2019 ISSUE 118, VOL.15 NO. 5
OBSERVING& EXPLORING
42 Binocular highlight
Open clusters in Centaurus
ByJonathanNally
44 Under the stars
The coloured stars of winter
ByFredSchaaf
46 Sun, Moon and planets
Saturn shines in Sagittarius
ByJonathanNally
47 Meteors
Duelling winter meteor showers
ByConStoitsis
48 Comets
Meet a very intriguing comet
ByDavidSeargent
49 Variable stars
Three target stars in Scorpius
By Alan Plummer
p.36 Solving the cosmic expansion conundrum
p.
What’s the mystery behind
this lunar landscape?
50 Exploring the Moon
Exploring a ghostly lunar feature
ByCharlesWood
52 Targets
Finding non-NGC star clusters
BySueFrench
55 Eclipse
Don’t miss July’s partial lunar eclipse
By Jonathan Nally