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October 2009 Celestial Calendar

Dave Mitsky

Note: All times in UTC (EST + 5)

The Orionid meteor shower peaks during the morning of October 21 and may be more productive than normal this year, with rates at dark sites of up to 30 per hour.

The Moon is 12.2 days old and is located in Aquarius on October 1 at 0:00 UT. The Moon occults Mars on October 12 and Antares on October 21. Browse http://www.lunar-occultations.com/iota/ for additional information on these occultations. The Lunar X occurs on October 25 at approximately 358 degrees co-longitude and the Curtiss Cross on October 12 at approximately 194 degrees co-longitude. The Moon reaches its greatest northern declination on October 9 (+26.1 degrees) and its greatest southern declination on October 22 (-26.0 degrees). Longitudinal libration is at a maximum of +5.6 degrees on October 19 and a minimum of -5.1 degrees on October 31. Latitudinal libration is at a maximum of +6.6 degrees on October 18 and a minimum of -6.5 degrees on October 5. Visit http://www.astronomyblogs.com/member/saberscorpx/?xjMsgID=50821 for tips on spotting extreme crescent Moons. 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 Lunar Crater Observation and Sensing Satellite (LCROSS) is scheduled to impact the lunar crater Cabeus A at 7:30 a.m. EDT on October 9. For further information, see http://www.nasa.gov/mission_pages/LCROSS/main/index.html and http://lcross.arc.nasa.gov/observation/amateur.htm

The zodiacal light may be visible in the pre-dawn eastern sky from a dark site, during the second half of the month.

The Sun is in Virgo on October 1 at 0:00 UT.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on October 1: Mercury (0.4 magnitude, 8.2", 28% illuminated, 0.82 a.u., Leo), Venus (-3.9 magnitude, 11.2", 90% illuminated, 1.48 a.u., Leo), Mars (0.8 magnitude, 6.6", 89% illuminated, 1.41 a.u., Gemini), Jupiter (-2.7 magnitude, 45.5", 99% illuminated, 4.33 a.u., Capricornus), Saturn (1.1 magnitude, 15.9", 100% illuminated, 10.42 a.u., Leo), Uranus (5.7 magnitude, 3.7", 100% illuminated, 19.22 a.u., Pisces), Neptune (7.9 magnitude, 2.3", 100% illuminated, 29.50 a.u., Capricornus), and Pluto (14.0 magnitude, 0.1", 100% illuminated, 32.08 a.u., Sagittarius).

During October, Jupiter and Uranus lie in the southeastern evening sky. At midnight, Jupiter is in the southwest and Uranus is in the south. Mercury, Venus, and Saturn can be seen in the east and Mars in the southeast in the morning sky.

Mercury reaches greatest eastern elongation on October 6 so the first half of the month is an ideal time to spot the speedy planet. Mercury, Venus, and Saturn are in close proximity during in early October. On October 8, Mercury and Saturn are only a third of a degree apart and can be seen in the same telescopic field of view.

Venus departs Leo and enters Virgo as the month progresses. It appears progressively lower in the morning sky as it slides sunward. On October 13, when Venus and Saturn pass within half a degree of each other, Venus shines more than 100 times brighter than the Ringed Planet.

Mars brightens to magnitude 0.5 and increases in apparent size from 6.6 to 7.9 arc seconds as it moves eastward from Gemini to Cancer during the course of October. The Red Planet approaches the open cluster M44 at the end of October and passes within its borders on the night of October 31.

Jupiter decreases in apparent size by almost 10% this month. Two mutual events involving the Jovian moons occur in the latter part of October. Ganymede occults Europa from 8:31 to 8:40 p.m. EDT on October 23 and Io occults Europa for almost 7 minutes starting around 9:18 p.m. EDT on October 24. A table of mutual events for the remainder of the year appears on page 59 of the October issue of Sky & Telescope. Click on http://skyandtelescope.com/observing/objects/planets/article_107_1.asp to determine transits of the central meridian by the Great Red Spot. Data on the Galilean satellites is available at http://www.skyandtelescope.com/observing/objects/javascript/3307071.html

Saturn is conjunction with Mercury on October 8 and Venus on October 13. Saturnss ring tilt angle is 2.3 degrees on October 15. Saturn rises about an hour before astronomical twilight by the middle of the month. On the morning of October 16, a thin crescent Moon joins Mercury, Venus, and Saturn in the eastern sky.

Uranus can be found five degrees south of the fourth-magnitude star Lambda Piscium, the southeastern-most member of the Circlet of Pisces.

This month Neptune is located approximately 2 degrees north of the third-magnitude star Delta Capricorni and just east of the fifth-magnitude star 42 Capricorni. See page 64 of the October 2009 issue of Astronomy for a finder chart.

Finder charts for Uranus and Neptune appear on page 59 of the September 2009 issue of Sky & Telescope and are posted online at http://www.skyandtelescope.com/observing/highlights/41561382.html

The dwarf planet Pluto is located about a degree to the east of the tenth-magnitude open cluster NGC 6507 in the northwestern portion of Sagittarius. A finder chart is available on page 53 of the June 2009 issue of Sky & Telescope.

Asteroid 3 Juno shines at eighth-magnitude as it passes southwestward through eastern Aquarius this month. Other asteroids reaching opposition this month include 18 Melpomene (magnitude 7.9), 148 Gallia (magnitude 10.9), 164 Eva (magnitude 11.0), 173 Ino (magnitude 10.5), and 455 Bruchsalia (magnitude 10.9).

Comet C/2006 W3 (Christensen) heads southward through Aquila and Scutum during October. On October 16, the eighth-magnitude comet is approximately one degree to the east of the third-magnitude star Lambda Aquilae. Comet C/2007 Q3 (Siding Spring) appears a few degrees from Venus in early October. It passes 15 arc minutes north of the eleventh-magnitude spiral galaxy NGC 3705 in Leo on October 22.

Binary and Multiple Stars for October

Struve 2973, Struve 2985, Struve 2992, Struve 3004, Struve 3028, Otto Struve 501, Struve 3034, Otto Struve 513, Struve 3050 (Andromeda); 29 Aquarii, 41 Aquarii, 51 Aquarii, 53 Aquarii, Zeta Aquarii, Struve 2913, Struve 2935, Tau-1 Aquarii, Struve 2944, Struve 2988, Psi-1 Aquarii, 94 Aquarii, 96 Aquarii, h3184, Omega-2 Aquarii, 107 Aquarii (Aquarius); Otto Struve 485, Struve 3037, 6 Cassiopeiae, Otto Struve 512, Sigma Cassiopeiae (Cassiopeia); Xi Cepheii, Struve 2883, Struve 2893, Struve 2903, Krueger 60, Delta Cephei, Struve 2923, Otto Struve 482, Struve 2947, Struve 2948, Struve 2950, Struve 2984, Omicron Cephei, Otto Struve 502 (Cepheus); Otto Struve 459, h1735, Struve 2876, Otto Struve 465, Struve 2886, Struve 2894, h1756, Struve 2902, Struve 2906, 8 Lacertae, Otto Struve 475, 13 Lacertae, h1828, 16 Lacertae (Lacerta); Struve 2857, Struve 2877, 34 Pegasi, Struve 2908, Xi Pegasi, Struve 2958, Struve 2978, 57 Pegasi, Struve 2991, h1859, Struve 3007, Struve 3021, Otto Struve 504, Struve 3044 (Pegasus); Struve 3009, Struve 3019, Struve 3033 (Pisces); Eta Piscis Austrini, Beta Piscis Austrini, Dunlop 241, h5356, Gamma Piscis Austrini, Delta Piscis Austrini, h5371 (Piscis Austrinus); h5417, Delta Sculptoris, h5429 (Sculptor)

Challenge binary star for October: 78 Pegasi

Notable carbon star for October: RZ Pegasi

* NGC 7320 is the brightest galaxy in Stephan's Quintet.
** NGC 7619 is the brightest member of Pegasus I.

Challenge deep-sky object for October: Jones 1 (PK104-29.1) (Pegasus)

Top ten binocular deep-sky objects for October: M52, NGC 7209, NGC 7235, NGC 7243, NGC 7293, NGC 7510, NGC 7686, NGC 7789, NGC 7790, St12

Top ten deep-sky objects for October: K12, M52, NGC 7209, NGC 7293, NGC 7331, NGC 7332, NGC 7339, NGC 7640, NGC 7662, NGC 7789

The objects listed above are located between 22:00 and 24:00 hours of right ascension.