Sky and Telescope - June 2015 - 49

Fred Schaaf

To ﬁnd out what's visible in the sky from your location, go to skypub.com/almanac.

December
solstice

O R B IT S O F THE P L ANE T S
The curved arrows show each planet's movement
during June. The outer planets don't change position
enough in a month to notice at this scale.

March
equinox

Sept.
equinox

Sun
Mercury

Venus

power telescopic ﬁeld of view, with Venus
- which starts the month only 22″ wide
and ends it 32″ wide - essentially identical in apparent diameter to Jupiter! Their
globes otherwise contrast dramatically,
with dazzlingly clouded Venus only 34%
lit and the far more dully clouded (but
detailed) Jupiter 100% lit. Venus is currently 7.4 times closer to the Sun than is
Jupiter, so Venus's surface is illuminated
by the Sun 55 times as brightly! This is
the same diﬀerence in surface brightness
they'll display in your telescope.

Mars

Earth June solstice

Jupiter
Uranus
Saturn

Neptune
Pluto

FROM DUSK TO NEAR DAWN
Saturn was at opposition on May 22nd so
in June is already visible in the southeast
at nightfall, not setting until morning
twilight. Saturn dims a bit - from magnitude +0.1 to +0.2 - as it retrogrades in
eastern Libra, still only about 3° from the
ﬁne double star Beta (β) Scorpii. During
the second half of the month, the ringed
planet transits in the south in late evening
before Venus and Jupiter set. This is the
ideal time to observe Saturn's globe (more
than 18″ wide this month) and its rings,

Dusk, June 28 -29
1 hour after sunset
Moon
June 29

which in June span more than 41″ and are
tilted a wide 24° from edgewise.
Uranus and Neptune are still not very
high at dawn's ﬁrst glow (see skypub.com/
urnep for a ﬁnder chart). Pluto reaches
opposition in July.

DAWN
Mercury was at inferior conjunction
on May 30th and now climbs gradually
into the dawn. But even when Mercury

Dusk, June 30

Moon
June 28

1 hour after sunset

Saturn

Antares

LEO

SUN AND MOON

Regulus

SCORPIUS

Looking South-Southeast

Only 1 3°
apart!

reaches greatest western elongation from
the Sun on June 24th, it brightens to only
magnitude +0.5 and is only about 35% lit.
Have a look for it that morning anyway;
bring binoculars and scan low in the
east-northeast as dawn brightens. Just 2°
to Mercury's lower right will be slightly
dimmer Aldebaran.
Mercury is a bit higher and brighter
by month's end, but still only about 6° or
7° above the horizon around 45 minutes
before sunrise.
Mars passes through conjunction with
the Sun on June 14th, and so it's not visible this month.

Jupiter
Venus

Looking West

The Sun arrives at the solstice at 12:38
p.m. EDT on June 21st, commencing
summer in the Northern Hemisphere
and winter in the Southern Hemisphere.
The Moon is less than one day short of
full when it shines less than 6° lower left
of Saturn at dusk on June 1st. The waxing
crescent Moon is directly below Venus at
dusk on June 19th. Then, on June 20th,
it glows farther left of Venus - but only
about 6° lower left of Jupiter. The next
night, the thickening lunar crescent is
left of Regulus. At nightfall on June 28th,
the waxing gibbous Moon is less than 2°
upper left of Saturn. ✦
Sk yandTelescope.com June 2015

49
http://www.skypub.com/almanac http://www.skypub.com/urnep http://www.skypub.com/urnep http://www.SkyandTelescope.com
Sky and Telescope - June 2015

Table of Contents for the Digital Edition of Sky and Telescope - June 2015
