The path ofJupiter
against the background stars of Libra, Scorpius,
Ophiuchus
and Sagittarius from December 2005 to January
2009, with positions marked at the start
of each month. Periods of invisibility (i.e. when the planet is
too close to the Sun, or passes behind it) are indicated by a dashed
line. Hence the planet became lost from view (in the evening sky) in
early November 2006 and became visible again (in the morning
sky) in early December 2006. The chart shows to good effect how the shape
of a planet's apparent looping formation transforms as it moves
through the zodiac. In 2006, Jupiter described a conventional North-facing loop.
In 2007, the loop became 'hybrid' (half loop, half zig-zag)
and will become a full zig-zag as it crosses the ecliptic (heading
Southwards) in 2008. The
star map applies to observers
in the Northern hemisphere (i.e. North is up); for the Southern hemisphere view, click here
(the Southern hemisphere chart
should be used by observers situated
south of the Tropic
of Capricorn
[23½° South]).
The Milky Way is shown in dark grey; the faintest stars shown on the map have
an apparent
magnitudeof about
+4.8.
Printer-friendly versions of this chart are available
for Northern
and Southern
hemisphere views.
Throughout
2006, Jupiter was
seen in the constellation of Libra,
the Scales, where it had been situated since late 2005. The planet entered Scorpius,
the Scorpion, in early December 2006 and entered the non-zodiac constellation
of Ophiuchus,
the Serpent Bearer, at the end of that same month.
Jupiter
in Virgo, 2005
Jupiter was situated in the
constellation of Virgo when this picture was taken in January 2005. Jupiter
(then magnitude -2.0)
greatly outshone Spica, the brightest star in Virgo (magnitude +1.2) which
is seen at
the bottom left of the picture. The planet will
return to this position in the sky in late 2016, i.e. after it has
completed one Jovian orbit (11.8 Earth years)
(Move
your pointer over the image to identify the stars, and click for a full screen picture).
Jupiter's
entire 'hybrid' loop formation was described within the boundary of Ophiuchus,
after which it continued Eastwards (direct motion)
through to early December 2007, when the planet entered Sagittarius,
the Archer. Jupiter
will remain in Sagittarius
until early January 2009, when it will cross the boundary into Capricornus,
the Sea Goat. For more information on Sagittarius,
and instructions on how to find it, see the Find
Sagittarius page.
Jupiter
reaches opposition
to the Sun
(when it is closest to the Earth and brightest in the sky for the year) every
398.88 days on average, i.e. about 33½ days later in each successive year.
For the period covered by the above star map, oppositions take place
on May 4th 2006,
June 5th 2007
and July 9th 2008.
Around opposition, the planet is due South at local midnight in the Northern
hemisphere (due
North at local midnight in the Southern hemisphere).
The
apparent size
of the planet (i.e. its angular size as seen from the Earth, measured in arcseconds)
at each successive opposition is 44".6 (on May 4th 2006) increasing to 45".7
(on June 5th 2007) and 47".2 (on July 9th 2008).
Note that, because of
the planet's rapid rotation speed, Jupiter's disk
appears as an oblate spheroid through telescopes and high-magnification
binoculars (i.e. it appears flattened at the poles and bulged at the equator).
The dimension given above is the apparent
equatorial
diameter of
the planet; its apparent
polar
diameter is
about 6.5% less.
The apparent
magnitude of the planet varies during the period shown
in the star chart from -2.7
(at opposition)
to -1.7
(at superior
conjunction),
making it considerably brighter than any of the stars shown (the brightest star
shown is ruddy-coloured Antares, a red supergiant whose apparent
magnitude
ranges from +0.9 to +1.1 over a 5 year period. In 2007, the presence of brilliant white Jupiter near
the orange-red Antares
provided a good opportunity to observe their contrasting colours).
Jupiter in
morning twilight, filmed with
a video camera in October 2004, about half an hour before sunrise.
In April 2005 Jupiter
passed the aphelion point
of its orbit (i.e. its furthest point
from the Sun; in
this case 5.46 Astronomical
Units or 816 million kms) and consequently was
at its most poorly-placed orbital position when observed from the Earth. The
situation has since improved and at opposition in September 2010 - when the planet is located
in southern Pisces
- it will be seen at its brightest and best for its entire 11.8-year orbit.
It's apparent equatorial diameter will then measure 49".6
and it will shine at magnitude -2.9.
Jupiter's
perihelion (i.e.
its closest
point to the Sun,
at 4.95 AU or 740 million kms) will be reached six months later,
in March
2011.
Observing
Circumstances, 2007 to 2008
For
observers at mid-Northern latitudes, Jupiter will be seen
low down in the sky
for the next few years, as the planet traverses the Southernmost constellations of the zodiac.
For 2007-8, when at meridian
transit
(due South), the planet will appear at its lowest angular elevation
in the sky for some twelve years. Observing circumstances gradually improve from 2009, as the planet begins
to ascend the ecliptic once more, moving North-eastwards
through Capricornus.
Conversely, for the next number
of years, observers in mid-Southern latitudes will see Jupiter high
up in the sky when it reaches meridian transit (due North) providing optimal viewing conditions for telescopic observers.
Moon
near
Jupiter Dates, September 2007 to December 2008
The Moon is easy to find, and on one
or two days in each month, it passes Jupiter
in the sky. Use the following table to see on which dates the Moon will
be in the vicinity of the planet:
Date
Range
(World)
Conjunction
(Geocentric)
Moon
Phase
Date
& Time
Separation
2007
Sep
18/19
Sep
18, 15:01 UT
5°.6
Waxing
Crescent
Oct 15/16
Oct
16, 05:36 UT
5°.3
Waxing
Crescent
Nov
12/13
Nov
12, 21:45 UT
5°.0
Waxing
Crescent
2008
Jan
6/7
Jan 7, 10:09 UT
4°.3
Waning
Crescent
Feb
3/4
Feb 4, 05:48 UT
4°.0
Waning
Crescent
Mar
2/3
Mar
3, 00:52 UT
3°.6
Waning
Crescent
Mar
30/31
Mar
30, 17:19 UT
3°.2
Waning Crescent
Apr
26/27
Apr
27, 05:07 UT
2°.7
Waning
Gibbous
May
24
May
24, 11:15 UT
2°.4
Waning
Gibbous
Jun
20/21
Jun
20, 12:40 UT
2°.4
Waning
Gibbous
Jul
17/18
Jul
17, 12:23 UT
2°.6
Waxing
Gibbous
Aug
13/14
Aug
13, 14:09 UT
2°.8
Waxing
Gibbous
Sep
9/10
Sep
9, 20:22 UT
2°.8
Waxing
Gibbous
Oct
6/7
Oct
7, 07:18 UT
2°.5
First
Quarter
Nov
3/4
Nov
3, 21:51 UT
1°.9
Waxing
Crescent
Dec
1/2
Dec
1, 14:42 UT
1°.3
Waxing
Crescent
Dec
28/29
Dec
29, 09:04 UT
0°.6
Waxing
Crescent
On
December 1st, 2008,
Jupiter, Venus and the four-day-old Moon will form an
impressive celestial grouping in the evening sky. This
is the author's simulation of how the event will appear
to residents of Cairo, Egypt, at the end of evening
twilight (around 1810 Local Time), when the group will
be situated low down in the South-western sky. Venus
(at left of picture) will be an 'Evening Star'
at magnitude -4.0 and Jupiter will be at magnitude -1.8 (closing
in on the Sun, heading towards superior
conjunction)
at the time of the event. Although the three bodies
appear to form a tight triangle in this
image, the actual positioning of the Moon in
relation to Jupiter and Venus will vary depending upon your location
on the Earth and the time at which you observe.
On
the same day, observers
in Europe and North-west Africa will see the Moon pass
in front of Venus (in an event called a lunar occultation)
around local sunset/dusk - for more details see the IOTA
website.
Moon
nearJupiter
dates for the period from September
2007 to December 2008 (no entry is given for December
2007 because Jupiter was too close to the Sun -
and was therefore not visible - when the Moon was nearby). The Date Range shows the range of dates worldwide (allowing for
Time Zone differences across East and West hemispheres).
Note that the Date, Time and
Separation of conjunction (i.e. when
the two bodies are at the same celestial longitude) are measured from the Earth's centre (geocentric) and
not from the Earth's surface (times are Universal
Time [UT], equivalent to GMT). The Moon Phase shows whether
the Moon is waxing
(between New Moon and Full Moon), waning
(between Full Moon and New Moon), at crescent
phase (less
than half of the lunar disk illuminated) or gibbous
phase
(more than half but less than fully illuminated).
The Moon moves relatively
quickly against the background stars (in an Eastward direction, at about its own angular width [0º.5] each
hour, or about 12º.2 per day) and because it is relatively close to the Earth,
an effect called parallax causes it to appear in a slightly different position (against the background
stars) when seen from any two locations on the globe at any given instant;
the further apart the locations, the greater the Moon's
apparent displacement against the background stars. Therefore, for any given date
and time listed in the table, the Moon will
appear closer to Jupiter
when seen from some locations than from others. For this reason, the dates shown
in the table should be used only for general guidance.
Current
Position of Jupiter's
Four Brightest Moons
Jupiter's
four brightest satellites
(moons) - namely Ganymede(magnitude +4.6),
Io
(+5.0),
Europa
(+5.3)
and Callisto (+5.6)
- can be seen through telescopes or steadily-held binoculars. The satellites are seen to change their position
in relation to each other, along the planet's equatorial plane,
from one night to the next. In fact, their motion can be detected
in the space of just a few hours.
This
Java applet shows Jupiter and the four satellites in their present
positions.
Their distances from Jupiter are shown in correct proportion to
that of the real Jovian system. North is up and East is to the left,
matching the Northern hemisphere view; Southern hemisphere observers
will need to invert the image to obtain the correct view.
The
left-to-right order of the displayed satellites are indicated by the satellite
names in the lower left box. If the name is in red,
it indicates that the satellite is being occulted
by Jupiter (i.e. it is passing behind the planet). If the
name is in yellow,
the satellite is passing in front of Jupiter (an event known as
a transit).
Satellite transits can be observed in larger telescopes, the satellite
appearing as a small black dot moving slowly against Jupiter's bright
disk.
Because
of their low magnification, binoculars may have some difficulty detecting Io
since it is the closest of the four satellites to Jupiter; it never
lies more than three Jupiter-diameters away. Europa
is easier, but Ganymede
is the easiest of the four to see. Callisto moves
furthest away from the planet, but it is also the faintest of the four.
The 'JupSat'
applet is produced by Gary Nugent and can be downloaded
free of charge from his website, Night
Sky Observer (if
you have Javascript disabled in your browser, the
Applet will not display).
The star chart was compiled using a variety of sources, including
the commercial software MegaStar
(by Willmann-Bell, Inc),
the freely-downloadable SFA Star Charts by
Dan Bruton and the
SkyGazer
Ephemeris utility
by
John Biondo. Star colours were based on those shown in "Patrick
Moore's Colour Star Atlas"
(Mitchell Beazley Publishers Ltd., London, 1973).
The
dates of the aphelion and perihelion
point crossings were
determined using SkyGazer
Ephemeris. Dates of
constellation boundary crossings were determined using MegaStar.
The
times and separations of the lunar conjunctions with Jupiter (Moon near Jupiter dates) and the lunar
phases were obtained from the commercial
software RedShift
5 by Maris Technologies
Ltd. using the 'Conjunctions'
option of the 'Sky Diary'. The range of worldwide dates were obtained
by determining the local times of the Moon and Jupiter conjunction at locations
situated in the far Eastern hemisphere (Fiji Islands, GMT+12 hours) and
the far Western hemisphere (Hawaiian Islands, GMT-10 hours).
