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June 2009 Astronomical Calendar

Dave Mitsky

Note: All times in UTC (EDT + 4)

The normally very minor Boötid meteor shower peaks on the morning on June 27.

An almost Full Moon occults the first magnitude star Antares on the night of June 6. See http://www.lunar-occultations.com/iota/bstar/0607antares.htm for further information. The Moon is 7.5 days old and is located in Leo on June 1 at 0:00 UT. The Moon is at its greatest northern declination of +26.4 degrees on June 22 and its greatest southern declination of -26.4 degrees on June 8. Longitudinal libration is at a maximum of +7.2 degrees on June 29 and a minimum of -7.6 degrees on June 17. Latitudinal libration is at a maximum of +6.7 degrees on June 4 and a minimum of -6.7 degrees on June 18. Times and dates for the lunar light rays predicted to occur in June are available at http://www.lunar-occultations.com/rlo/rays/rays.htm The Sun is located in Taurus on June 1. It reaches its farthest position north for the year on June 21, the day of the summer solstice.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on June 1: Mercury (magnitude 2.1, 10.7", 14% illuminated, 0.63 a.u., Taurus), Venus (magnitude -4.5, 25.2", 47% illuminated, 0.66 a.u., Pisces), Mars (magnitude 1.2, 4.7", 94% illuminated, 2.00 a.u., Aries), Jupiter (magnitude -2.5, 41.7", 99% illuminated, 4.72 a.u., Capricornus), Saturn (magnitude 0.9, 17.9", 100% illuminated, 9.28 a.u., Leo), Uranus (magnitude 5.8, 3.5", 100% illuminated, 20.10 a.u., Pisces), Neptune (magnitude 7.9, 2.3", 100% illuminated, 29.53 a.u., Capricornus), and Pluto (magnitude 13.9, 0.1", 100% illuminated, 30.66 a.u., Sagittarius). Saturn is located in the southwest in the evening and in the west at midnight this month. In the morning, Mercury, Venus and Mars can be found in the east, Jupiter in the south, and Uranus in the southeast. Mercury reaches greatest western elongation on June 13. It is half-illuminated on June 19 and remains visible through month's end. As June progresses, the disk of Venus shrinks from 25 to 19 arc seconds as its phase increases from 47 to 61% illuminated. Venus shines at magnitude -4.4 when it is at greatest elongation west on June 5. Venus dims slightly as the month unfolds but climbs higher into the morning sky. The planet is 50% illuminated on June 6.

Mars remains too small for worthwhile telescopic observation. On June 19, brilliant Venus passes two degrees south of Mars, an object which is some five magnitudes or 100 times more faint. A waning crescent Moon lies seven degrees above the pair. Jupiter begins its retrograde loop on June 15. On that date, Jupiter rises not long after midnight. Click on http://skyandtelescope.com/observing/objects/planets/article_107_1.asp to determine transit times of the central meridian by the Great Red Spot. Data on the Galilean satellites is available at http://skytonight.com/observing/objects/javascript/3307071.html Saturn reaches eastern quadrature on June 5. The ring tilt angle decreases from four to three degrees this month. The rings are inclined by 3.7 degrees on June 15. Eighth-magnitude Titan is eclipsed at 1:34 a.m. EDT on June 8 and at 12:45 a.m. EDT on June 24, but neither event is visible from the East Coast. A shadow transit takes place on June 15, starting at 11:40 p.m. EDT. On June 10, four of Saturn's other satellites (Tethys, Dione, Rhea, and Enceladus) form a parallelogram to the east of Saturn around 10:45 p.m. EDT. For further information on Saturn's satellites, browse http://skytonight.com/observing/objects/javascript/3308506.html Uranus lies to the south of the Circlet of Pisces, less than a degree to the north of the fifth-magnitude star 20 Piscium. During June, Neptune and Jupiter remain in close proximity to each other in the eastern portion of Capricornus. Neptune is 28 arc minutes northwest of Jupiter on June 1. The two planets separate to a span of 48 arc minutes by June 20 but draw closer again as June ends due to Jupiter's retrograde motion.

The dwarf planet Pluto is located in northwestern Sagittarius between the open clusters M18 and M23, some three degrees north of the fourth-magnitude star Mu Sagittarii. Pluto reaches opposition on June 23. Locating Pluto is even harder than usual this year since it is entering a star-rich section of the Milky Way. A finder chart is available on page 53 of the June 2009 issue of Sky & Telescope. The periodic comet 22P/Kopff glides eastward from Capricornus into Aquarius during June. This comet should reach eighth magnitude and is visible in the morning sky in the vicinity of Jupiter. Comet 2006/W3 (Christensen), located in Pegasus not far from the bright galaxy NGC 7331, is another fine cometary target this month. Browse http://www.aerith.net/comet/future-n.html for additional information on these comets.

Asteroid 1 Ceres travels southeastward through Leo this month. From June 18 to June 21, the fading (magnitude 8.4 to magnitude 8.7) asteroid passes close to the third-magnitude star Theta Leonis. Asteroids 22 Kalliope (magnitude 10.8) and 393 Lampetia (magnitude 10.6) are at opposition this month.

Binary and Multiple Stars for June

Struve 1812, Kappa Bootis, Otto Struve 279, Iota Bootis, Struve 1825, Struve 1835, Pi Bootis, Epsilon Bootis, Struve 1889, 39 Bootis, Xi Bootis, Struve 1910, Delta Bootis, Mu Bootis (Bootes); Struve 1803 (Canes Venatici); Struve 1932, Struve 1964, Zeta Coronae Borealis, Struve 1973, Otto Struve 302 (Corona Borealis); Struve 1927, Struve 1984, Struve 2054, Eta Draconis, 17-16 Draconis, 17 Draconis (Draco); 54 Hydrae (Hydra); Struve 1919, 5 Serpentis, 6 Serpentis, Struve 1950, Delta Serpentis, Otto Struve 300, Beta Serpentis, Struve 1985 (Serpens Caput); Struve 1831 (Ursa Major); Pi-1 Ursae Minoris (Ursa Minor); Struve 1802, Struve 1833, Phi Virginis (Virgo)

Challenge binary star for June: Gamma Coronae Borealis

Notable carbon star for June: V Coronae Borealis

Challenge deep-sky object for June: Abell 2065

Top ten deep-sky objects for June: M5, M101, M102, NGC 5566, NGC 5585, NGC 5689, NGC 5746, NGC 5813, NGC 5838, NGC 5907

Top five deep-sky binocular objects for June: M5, M101, M102, NGC 5466, NGC 5907