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Dave Mitsky
2005-Jul-01, 01:51 PM
July Calendar by Dave Mitsky

All times are UT (subtract 4 hours and when appropriate 1 calendar day for EDT)

7/1 The Galilean satellites Io, Europa, and Callisto are all close to the eastern limb of Jupiter at 9:40; a double Galilean satellite shadow transit (Io's shadow is followed by Europa's) begins at 13:12
7/2 The Moon is 0.8 degree south of the bright open star cluster M45 (the Pleiades) at 20:00
7/3 Mercury is 0.9 degree south of the bright open star cluster M44 (the Beehive Cluster) at 19:00
7/4 Maximum lunar libration of 7.1 degrees occurs at 5:00; Venus is 0.06 degree north of M44 at 5:00; a double Galilean satellite transit (Io is followed by Europa) begins at 23:56
7/5 Venus is at its greatest heliocentric latitude north; Earth reaches aphelion (152,102,378 km from the Sun) at 5:00
7/6 New Moon (lunation 1021) occurs at 12:02
7/7 Mercury is at the descending node; a seventh magnitude star is approximately 1' north of Mars; Mercury is 1.6 degrees south of Venus at 8:00
7/8 A double Galilean satellite transit (Io is followed by Europa) begins at 13:15; the Moon is at apogee, subtending 29'24" at a distance of 406,363 km, at 17:39; Mercury is 5 degrees south of the Moon at 18:00; Venus is 3 degrees south of the Moon at 19:00
7/9 Mercury is at greatest eastern elongation (26 degrees) at 3:00
7/10 Minimum lunar libration of 5.6 degrees occurs at 19:00
7/12 A double Galilean satellite transit (Io is followed by Europa) begins at 2:35
7/13 Jupiter is 0.8 degree north of the Moon (an occultation occurs in most of South America and part of Antarctica) at 18:00
7/14 First Quarter Moon occurs at 15:20
7/15 A double Galilean satellite transit (Io is followed by Europa) begins at 15:55
7/17 Maximum lunar libration of 8.4 degrees occurs at 9:00; Mars is at perihelion at 16:00
7/18 The Moon passes 0.6 degrees north of the first magnitude star Antares (an occultation occurs in the southern and western USA, the Caribbean, and northern South America) at 4:00
7/21 The Full Moon, known as the Hay or Thunder Moon and the largest of 2005, occurs at 11:00; the Moon is at perigee, subtending 33'27" at a distance of 357,159 km, at 20:00 - large tides will result
7/22 Mercury is stationary at 5:00; Neptune is 4 degrees north of the Moon at 13:00; Venus passes 1.2 degrees north of Regulus at 15:00
7/23 Minimum lunar libration of 6.0 degrees occurs at 1:00; Saturn is in conjunction with the Sun at 17:00
7/24 Uranus is 2 degrees north of the Moon at 3:00
7/27 Mars nearly occults a seventh magnitude star at 19:27; Mars is 4 degrees south of the Moon at 20:00
7/28 The southern Delta Aquarid meteor shower (approximately 20/hour) peaks at 1:00; Last Quarter Moon occurs at 3:19
7/30 Maximum lunar libration of 8.2 degrees occurs at 2:00; the Moon is 0.6 degree south of M45 at 2:00

Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occultations.com/rlo/rays/rays.htm

The planets on July 1: Mercury (0.1 magnitude, 6.9", 55% illuminated), Venus (-3.7 magnitude, 11.0", 91% illuminated), Mars (-0.1 magnitude, 9.3", 84% illuminated), Jupiter (-2.0 magnitude, 36.8", 99% illuminated), Saturn (0.2 magnitude, 16.5", 100% illuminated), Uranus (5.8 magnitude, 3.6", 100% illuminated), Neptune (7.8 magnitude, 2.3", 100% illuminated), and Pluto (13.8 magnitude, 0.1", 100% illuminated).

Mercury is in conjunction with Venus on July 7. It is 26 degrees east of the Sun on the night of July 8, when it lies low in the west-northwest, just to the south of Venus and a 6% illuminated crescent Moon. By the middle of July, Mercury is lost in the Sun's glare.

Venus and Mercury are 1.0 degree apart on July 1. Although at 16 degrees above the horizon it is not particularly well placed, Venus remains an easy target throughout the month. It sets about an hour and a half after the Sun.

Situated in Pisces, Mars enters the range of favorable telescopic observing when it reaches perihelion on July 17 and subtends 10" in apparent size. Mars is at western quadrature on July 12 and thus appears slightly gibbous.

Jupiter reaches eastern quadrature on July 1. Since Jupiter's shadow is then being cast farther eastward, eclipses of the Galilean satellites are enhanced. Jupiter sets around 11:00 p.m. EDT by month's end.

Saturn is no longer visible after the first week of July.

Uranus is approximately 1 degree away from the third magnitude star Lambda Aquarii on July 1.

In early part of the month, Neptune is located about halfway between fourth magnitude Iota Capricornii and fifth magnitude 29 Capricornii. By the end of the month, the planet's retrograde movement places it 0.9 degree to the south of 29 Capricornii.

Pluto is well placed in the southern sky on July evenings. It is 1.9 degrees to the west of Xi Serpentis as the month begins. Pluto is another 0.5 degree farther west from Xi by the end of July.

During the early morning of July 4, the periodic comet 9P/Tempel lies to the east of the first magnitude star Spica, the lucida of Virgo. The impact of a projectile launched from the Deep Impact spacecraft may cause the dim comet to brighten by as much as four magnitudes. Unfortunately, at the predicted time of the impact, 9P/Tempel is below the horizon for observers in most of the United States. Be sure to look for the comet low in the west on subsequent evenings.

Another periodic comet, ninth magnitude 161P/Hartley-IRAS, passes the Double Cluster on the night of July 29 and is midway between Ursa Major and Polaris at month's end.

Yet another periodic comet, tenth magnitude 21P/Giacobini-Zinner, is just a bit west of the bright open cluster M45 (the Pleiades) on the mornings of July 1 and July 2.

Asteroid 1 Ceres is located to the north of the second magnitude star Alpha Librae (Zubenelgenubi) as the eighth magnitude minor planet travels southeastward through Libra.

Forty binary and multiple stars for July: Eta Draconis, 17 & 16 Draconis, Mu Draconis, Struve 2273, Nu-1 & Nu-2 Draconis, Psi Draconis (Draco); Kappa Herculis, Gamma Herculis, Struve 2063, 56 Herculis, Struve 2120, Alpha Herculis (Ras Algethi), Delta Herculis, Rho Herculis, Mu Herculis (Hercules); Rho Ophiuchi, Lambda Ophiuchi, 36 Ophiuchi, Omicron Ophiuchi, Burnham 126 (ADS 10405), Struve 2166, 53 Ophiuchi, 61 Ophiuchi (Ophiuchus); h5003 (Sagittarius); Xi Scorpii, Struve 1999, Beta Scorpii, Nu Scorpii, 12 Scorpii, Sigma Scorpii, Alpha Scorpii (Antares), h4926 (Scorpius); Struve 2007, 49 Serpentis, Struve 2031 (Serpens Caput); 53 Serpentis, Struve 2204, h4995, h2814 (Serpens Cauda); Epsilon Ursae Minoris (Ursa Minor)

Challenge binary star for July: 24 Ophiuchi

Sixty-five deep-sky objects for July: NGC 6140, NGC 6236, NGC 6340, NGC 6395, NGC 6412, NGC 6503, NGC 6543 (Draco); IC 4593, M13, M92, NGC 6106, NGC 6166, NGC 6173, NGC 6181, NGC 6207, NGC 6210, NGC 6229, NGC 6482 (Hercules); B61, B62, B63, B64, B72, IC 4634, IC 4665, LDN 42, LDN 1773, M9, M10, M12, M14, M19, M62, M107, NGC 6284, NGC 6287, NGC 6293, NGC 6304, NGC 6309, NGC 6356, NGC 6366, NGC 6369, NGC 6384, NGC 6401, Tr 26 (Ophiuchus); NGC 6440, NGC 6445 (Sagittarius); B50, B55, B56, Cr 316, M4, M6, M7, M80, NGC 6144, NGC 6153, NGC 6192, NGC 6231, NGC 6242, NGC 6302, NGC 6337, NGC 6451 (Scorpius); NGC 6217, NGC 6324 (Ursa Minor)

Challenge deep-sky object for July: NGC 6380