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[Chicago Astronomer - Astro Joe]

August 2006 Sky Calender

8/1 Today is Lammas, one of the cross-quarter days; the Moon is 0.4
degree south of the first magnitude star Spica (an occultation takes
place in southern South America) at 1:00
8/2 Jupiter is 3.6 degrees north-northeast of the Moon at 8:00; First
Quarter Moon occurs at 8:46; Jupiter reaches eastern quadrature at
12:00
8/3 A double Galilean shadow satellite transit (Europa's shadow is
followed by Io's) takes place from 16:11 to 16:23; Venus is at the
ascending node at 21:00
8/4 The Moon is 0.4 degree south of the first magnitude star Antares
(an occultation takes place in southern South Africa and northeastern
South America) at 18:00
8/5 Asteroid 6 Hebe (magnitude 7.8) reaches opposition at 0:00; a
maximum lunar libration of 9.6 degrees occurs at 7:00
8/7 Mercury is at greatest western elongation (19.2 degrees) at 0:00;
a double shadow transit (Europa's shadow is followed by Io's) takes
place from 5:08 to 5:41; Saturn is in conjunction with the Sun at
11:00
8/8 Summer solstice occurs on Mars at 1:00
8/9 Full Moon, known as the Grain or Green Corn Moon, occurs at 10:54
8/10 The Moon is at perigee, subtending 33'13" from a distance of
359,750 km at 18:00; a double Galilean shadow satellite transit
(Europa's shadow is followed by Io's) takes place from 18:05 to
19:01; the Sun enters Leo (ecliptic longitude 138.0 degrees) at
19:00; Mercury (magnitude -0.4) is 2.2 degrees southeast of Venus
(magnitude -3.9) at 21:00
8/11 Neptune (magnitude 7.8, angular size 2.3") reaches opposition at
5:00; Uranus is 0.3 degree north of the Moon (an occultation takes
place in western Africa and most of South America) at 6:00; a minimum
lunar libration of 1.7 degrees occurs at 10:00
8/12 The Moon is at the ascending node (longitude 355.8 degrees) at
6:00; Asteroid 1 Ceres (magnitude 7.6) is at opposition at 15:00; the
peak of the Perseid meteor shower (approximately 60/hour) occurs at
23:00
8/13 Mercury is at the ascending node at 6:00
8/14 A double Galilean shadow satellite transit (Europa's shadow is
followed by Io's) takes place from 7:03 to 8:19
8/16 Mercury is 0.73 degree south-southwest of center of the bright
open cluster M44 (the Beehive Cluster) at 1:00; Last Quarter Moon
occurs at 1:51; the Moon is 0.69 degree north of the center of the
bright open cluster M45 (the Pleiades) at 15:00
8/17 Mercury is at perihelion at 22:00
8/18 A maximum lunar libration of 9.6 degrees occurs at 3:00; Venus
is 0.67 degree south of the center of M44 at 23:00
8/19 A double shadow transit (Ganymede's shadow is followed by Io's)
takes place from 14:29 to 14:55
8/20 The Moon is 2.1 degrees south of the first magnitude star Pollux
at 18:00
8/21 Mercury (magnitude -1.3) is 0.50 degree north-northeast of
Saturn (magnitude 0.4) at 0:00; a double shadow transit (Europa's
shadow is followed by Io's) takes place from 8:57 to 10:57; the Moon
is 2.3 degrees north-northeast of M44 at 21:00
8/22 Neptune is 4 degrees north of the Moon at 13:00; Venus passes
1.2 degrees north of the first magnitude star Regulus at 15:00
8/23 Only one of the Galilean satellites, namely Callisto, will be
visible from 3:14 to 4:23; the Moon is 1.8 degrees north-northeast of
Regulus at 19:00; New Moon (lunation 1035) occurs at 19:10
8/24 Uranus is 2 degrees north of the Moon at 3:00; Asteroid 2 Pallas
is stationary at 10:00; Europa, Io, and Ganymede form a tight group
just after 13:30; a double shadow transit (Europa's shadow is
followed by Io's) takes place from 21:55 to 0:03
8/25 Mars is 0.6 degree north of the Moon (an occultation takes place
in the northeast and central regions of South America) at 14:00; a
minimum lunar libration of 0.3 degree occurs at 18:00; the Moon is at
the descending node (longitude 175.4 degrees) at 21:34
8/26 The Moon is at apogee, subtending 29'25" from a distance of
406,269 km, at 1:00; a double shadow transit (Io's shadow is followed
by Ganymede's) takes place from to 17:05 to 18:31; Venus (magnitude -
3.9) is 0.08 degree north-northeast of Saturn (magnitude 0.5) at
23:00
8/27 Mercury is 1.3 degrees north-northeast of Regulus at 19:00
8/28 Mercury is at its greatest latitude north of the ecliptic plane
(7.0 degrees) at 4:00; the Moon is 0.6 degree southwest of Spica (an
occultation takes place in southern New Zealand and Madagascar) at
8:00; a double shadow transit (Io's shadow is followed by Europa's)
takes place from 11:02 to 13:00
8/29 Jupiter is 4.8 degrees north-northwest of the Moon at 22:00
8/31 First Quarter Moon, the second of the month, occurs at 22:57

A rising gibbous Moon compromises the Perseid meteor shower this
year. Due to the bright moonlight, only about half of the usual
hourly rate of Perseids may be visible.

On the morning of August 22, the thin crescent Moon, Mercury, Venus,
and Saturn lie within a 7.5 degree diameter circle. Times and dates
for the lunar light rays predicted to occur this month are available
at www.lunar-occultations.com/rlo/rays/rays.htm

The planets on August 1: Mercury (1.2 magnitude, 9.0", 21%
illuminated, Gemini), Venus (-3.7 magnitude, 10.9", 92% illuminated,
Gemini), Mars (1.8 magnitude, 3.7", 98% illuminated, Leo), Jupiter (-
2.1 magnitude, 37.3", 99% illuminated, Libra), Saturn (0.3 magnitude,
16.3", 100% illuminated, Cancer), Uranus (5.7 magnitude, 3.7", 100%
illuminated, Aquarius), Neptune (7.8 magnitude, 2.3", 100%
illuminated, Capricornus), and Pluto (13.9 magnitude, 0.1", 100%
illuminated, Serpens Cauda).

Mercury is at greatest elongation from the Sun on August 7, when it
appears 10 degrees above the eastern horizon a half hour before
sunrise. For observers at 40 degrees north latitude, the speedy
planet is at its highest altitude of approximately 16 degrees on the
morning of August 9. Mercury is in quasi-conjunction with Venus on
August 10, the last such event involving bright planets until 2010. A
quasi-conjunction occurs when two planets pass within five degrees of
each other without reaching the same ecliptic longitude or right
ascension.

Venus rises less than two hours before the Sun and has close
encounters with Mercury and Saturn this month. The second closest
planetary appulse of 2006 occurs on August 26 when Venus and Saturn
are less than a tenth of a degree apart.

By the end of August, Mars sets only 45 minutes after the Sun and is
lost in its glare. The Red Planet is 5 degrees to the lower left of a
young crescent Moon on the evening of August 25. Mars wanders from
Leo into Virgo late in the month.

Jupiter moves three degrees closer to Zubenelgenubi (Alpha Librae)
during the course of the month. The fifth planet is at eastern
quadrature on August 2. This means that Jupiter is 90 degrees to the
east of the Sun. As a result, eclipses of the Galilean satellites,
with the exception of the non-eclipsing Callisto, will be more
readily observable, since Jupiter's shadow extends farther to the
east. Because Ganymede enters the shadow well to the east of the
planetary disk, it provides the best eclipse views. There are an
unusually high number of double shadow transits this month. (Few of
them are visible from our location.) Red Spot Junior has passed by
the Great Red Spot (GRS), apparently without incident. To determine
the transit times of the GRS, click on
skyandtelescope.com/observing/objects/planets/article_107_1.asp

Saturn disappears from view early in the month but reappears in the
morning sky by the third week of August. The Ringed Planet will be
about one degree below Mercury on the morning of August 20. Mercury
passes Saturn on August 21 and Venus on August 27.

During August, the seventh planet can be found to the east-northeast
of the third magnitude star Lambda Aquarii. Uranus passes within 0.1
degree of the sixth magnitude star 81 Aquarii on August 6. The
westward motion of Uranus places it 1.3 degrees east of Lambda
Aquarii at month's end.

When Neptune reaches opposition on the night of August 10, it is
situated 1.2 degrees to the north of Iota Capricornii (magnitude
4.3).

Pluto is positioned 0.5 degree southwest of Xi Serpentis (magnitude
3.5) on August 1. It will be an additional 0.8 degree farther away
from the star by the end of August.

The periodic comet 4P/Faye (period 7.5 years) glides northeastward
through Pisces during August. The tenth magnitude comet is 15' south
of the third magnitude star Eta Piscium on August 22. It passes just
south of the tenth magnitude spiral galaxy M74 on the nights of
August 26 and August 27.

The recently recovered periodic comet 177P/2006 M3 (Barnard 2) is
visible through a binocular on August evenings as an eighth magnitude
diffuse glow as it climbs through Hercules on its way to Draco. A
finder chart is posted at www.skyhound.com/sh/comets/177P.gif