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You are hereTHIS MONTH'S SKY - July 2010

THIS MONTH'S SKY - July 2010

THIS MONTH'S SKY
Celestial Events -- July 2010

 

 

THE BUSY WESTERN SKY GETS BUSIER

For the last few months we have been treated to Venus, Mars and Saturn in the western sky at dusk and into the early evening hours.  During this time the three have been closing in on each other.

In July things get even better, as Mercury becomes the fourth planet in the evening sky.  Though still rather close to the Sun in mid-July, Mercury should be spotted with the naked eye around then.  As the month proceeds, Mercury moves sharply south, making it more difficult to escape the Sun's twilight. Although its greatest elongation from the Sun won't occur until August 6, week-by-week Mercury's will be more difficult to see.  One highlight is its close conjunction with the bright star Regulus on July 17 -- the two are only 22' (arc minutes) apart.  (Venus passes just over one degree from Regulus on July 9).
Mercury, Venus, Mars, Mercury
9 PM July 1-31

 

Meanwhile, Venus, Mars and Saturn are slowly converging towards a three-way gathering in early August.  During July, Mars closes in on Saturn, and passes it at the end of the month.  For more information, check This Month's Sky for May.


JULY'S EVENING SKY

Click to get sky charts and a description of the sky for this month.
 

PLANETS IN JULY

 

MERCURY moves into the evening sky early in the month.  It may be visible as early as July 11.  In the middle of July it will have magnitude -0.5, dropping to +0.1 at the end of the month.  See above for more information.

VENUS (magnitude -4.1 to -4.3, diameter 15.5" to19.7", phase 71% to 59% lit) is by far the brightest object in the sky, after the Sun and Moon.  Although its distance from the Sun increases during July, the unfavorable angle of the ecliptic results in Venus moving well to the south. In July Venus crosses the length of Leo.  It sets about 11 PM on July 1 but shortly after 10 PM at the end of the month. Venus has a close conjunction with Regulus on the 9th and approaches to within 6° or 7° of Mars and Saturn at the end of July. For more about Venus, see May's Sky

MARS (magnitude +1.3 to +1.5, diameter 5.2" to 4.7") lies between Venus and Saturn.  It moves from Leo into Virgo on July 19.  Mars begins the month 15° from Saturn, but less than 2° at it passes the ringed planet at the end of the month. See May's Sky for more information.

JUPITER (magnitude -2.5 to -2.7, diameter 41.5" to 45.6"), in Pisces, rises just after midnight on July 1 and about 10:30 PM on July 31.  On July 23 it begins its retrograde motion (moving east to west with respect to the stars).

SATURN (magnitude +1.1, diameter 17.2" to 16.4") is in western Virgo.  Watch Mars approach it all month.  The two planets are less than 2° apart at the end of July.  See May's Sky for more information.

URANUS (magnitude +5.8, diameter 3.6") is in Pisces.  Jupiter is 2° to Uranus' right (west) as July begins, and 3° to its right at the end of the month.  Uranus begins its retrograde motion on the 5th.

NEPTUNE (magnitude +7.8, diameter 2.3") is in western Aquarius.

PLUTO (magnitude +14.0, diameter 0.1") is still in western Sagittarius.

The MOON is well upper right of Jupiter on July 3rd.  Last quarter Moon occurs the following day.  On the 11th the New Moon eclipses the Sun, totally for a few areas on Earth.  No part of the eclipse will be seen in the northern hemisphere.  The following evening the Moon is 5° below Mercury (use binoculars).  Two days later the Moon is below brilliant Venus.  On the 15th Mars and Saturn lie above the Moon.  Two days later the Moon is close to Spica, First Quarter occurs on the 18th, and three days later Antares is nearby.  Full Moon is on the 25th. On the morning of the last day of the month the Moon is again above Jupiter.

 

THIS MONTH'S EVENTS
(Times in EDT)

July 3 Jupiter is 8° south of the Moon this morning.
July 4 Last Quarter Moon at 10:35 AM.
July 5 Uranus is stationary, beginning retrograde motion.
July 6 Earth at aphelion (closest to Sun) -- 94,508,396 miles (152,096,520 kilometers).
July 8 The Moon is within a degree of the Pleiades this morning.
JULY 9 - 10 VENUS IS 1.1° UPPER RIGHT OF REGULUS ON THE 9TH, AND 1.1° ABOVE REGULUS THE NEXT NIGHT.
July 11 New Moon at 3:40 PM.  Total solar eclipse, but visible only in parts of the southern hemisphere.
July 12 Mercury is 5° above a thin crescent Moon in evening twilight.  Use binoculars.
July 14 Venus is 7° above the crescent Moon this evening.
July 15 Mars is 7° above the Moon and Saturn 10° above left of the Moon.
July 18 First Quarter Moon at 6:11 AM.
July 21 Antares is 4° right (west) of the Moon.
July 23 Jupiter is stationary, beginning retrograde motion.
July 25 Full Moon at 9:37 PM.
JULY 27 MERCURY IS ONLY 22' (⅓°) FROM REGULUS AT DUSK.  USE BINOCULARS.
JULY 29 - 31 MARS IS 1¾° BELOW SATURN IN THE EARLY EVENING SKY.
July 31 Jupiter is 7° south of the Moon.