October 2012 Celestial Calendar & Observing Notes c/o Dave Mitsky

[Big Dipper]

October 2012 Celestial Calendar & Observing Notes c/o Dave Mitsky

(calendar data also reproduced in our forum calendar).

*NB: Check out also the resources at the end of Dave's calendar for further reading/information*

All times unless otherwise noted are UT.

10/1 Mercury is 1.8 degrees north of the first-magnitude star Spica (Alpha Virginis) at 1:00

10/3 Venus is 0.1 degree south of the first-magnitude star Regulus (Alpha Leonis) at 8:00

10/4 Jupiter is stationary at 14:00

10/5 The Moon is at apogee, subtending 30 arc minutes from a distance of 405,160 kilometers (251,755 miles), at 1:00; Jupiter is 0.9 degree north of the Moon, with an occultation taking place in southern Australia, at 21:00

10/6 Mercury is 3 degrees south of Saturn at 7:00

10/7 Asteroid 1 Ceres is 0.9 degree north of the Moon, with an occultation taking place in southern Africa, at 21:00

10/8 Mercury is at aphelion today; the peak of the Draconid meteor shower (10 to 30 per hour) occurs at 2:00; Last Quarter Moon occurs at 7:33

10/9 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 1:18

10/12 Venus is 6 degrees north of the Moon at 19:00

10/15 The new moon (lunation 1111) occurs at 12:02

10/17 The Moon is at perigee, subtending 33 arc minutes from a distance of 360,672 kilometers (224,111 miles), at 1:00; Mercury is 1.3 degrees south of the Moon at 2:00

10/18 Mars is 2 degrees south of the Moon at 13:00

10/20 Mars is 4 degrees north of first-magnitude star Antares (Alpha Scorpii) at 6:00

10/21 The peak of the Orionid meteor shower (10 to 20 per hour) occurs at 4:00; asteroid 4 Vesta is stationary at 7:00

10/22 First Quarter Moon occurs at 3:32; the Lunar X, also known as the Purbach or Werner Cross, an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to occur at 11:01

10/24 Neptune is 6 degrees south of the Moon at 16:00

10/25 Saturn is in conjunction with the Sun at 8:00

10/26 Mercury is at greatest eastern elongation (24 degrees) at 22:00

10/27 Uranus is 5 degrees south of the Moon at 10:00

10/28 Mercury is at its greatest heliocentric latitude south today

10/29 Full Moon, known as the Blood Moon and this year’s Hunter’s Moon, occurs at 19:49

10/31 Venus is at aphelion; asteroid 1 Ceres is stationary at 21:00

Ejnar Hertzsprung and Henry Norris Russell were born this month.

Giovanni Cassini discovered Saturn’s odd satellite Iapetus on October 25, 1671. Two of the satellites of Uranus, Ariel and Umbriel, were discovered by William Lassell on October 24, 1851. Lassell discovered Triton, Neptune’s brightest satellite, on October 10, 1846.

The Draconid (formerly the Giacobinid) meteor shower peaks on the evening of October 8. The Orionid meteor shower peaks during the morning of October 21. The waxing crescent Moon sets as Orion rises in the east so conditions will be excellent. Orionid meteors are fragments of Comet 1P/Halley. A Taurid fireball swarm is a possibility from October 28 to November 11. Unfortunately, the Moon is full on October 29.

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

The Moon is 14.9 days old and is located in Pisces on October 1 at 0:00 UT. The Moon reaches its greatest northern declination on October 6 (+21.0 degrees) and its greatest southern declination on October 19 (-21.0 degrees). Longitudinal libration is at a maximum of +6.8 degrees on October 24 and a minimum of -6.7 degrees on October 11. Latitudinal libration is at a maximum of +6.8 degrees on October 11 and a minimum of -6.8 degrees on October 24. Large tides will occur from October 15 through October 18. Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon06.html for Full Moon data. Times and dates for the lunar light rays predicted to occur in October are available at http://www.lunar-occ...o/rays/rays.htm

The Sun is located in Virgo on October 1 at 0:00 UT. The first recorded solar eclipse took place on October 22, 2136 B.C.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on October 1: Mercury (magnitude -0.4, 5.0", 91% illuminated, 1.35 a.u., Virgo), Venus (-4.1 magnitude, 15.8", 71% illuminated, 1.06 a.u., Leo), Mars (magnitude 1.2, 4.8", 93% illuminated, 1.94 a.u., Libra), Jupiter (magnitude -2.5, 43.1", 99% illuminated, 4.58 a.u., Taurus), Saturn (magnitude 0.7, 15.5", 100% illuminated, 10.69 a.u., Virgo), Uranus (magnitude 5.7, 3.7", 100% illuminated, 19.06 a.u., Pisces), Neptune (magnitude 7.9, 2.3", 100% illuminated, 29.19 a.u., Aquarius), and Pluto (magnitude 14.1, 0.1", 100% illuminated, 32.31 a.u., Sagittarius).

During October evenings, Mercury and Mars are in the southwest, Saturn is in the west, Uranus is in the east, and Neptune is in the southeast. At midnight, Jupiter is located in the east, Uranus in the south, and Neptune in the southwest. Venus can be found in the east and Jupiter is in the southwest in the morning sky.

At midmonth, Mercury can be seen during evening twilight, Venus rises at 4:00 a.m. local time, Mars sets at 8:00 p.m. local time, Jupiter rises at 9:00 p.m. local time and crosses the meridian at 4:00 a.m. local time, and Saturn sets at 7:00 p.m. local time for observers at latitude 40 degrees north.

The finest evening apparition of Mercury for southern hemisphere observers takes place this month. Mercury passes 1.8 degrees north of Spica on October 1, three degrees south of Saturn on October 6, and close to the Moon on the evening of October 16. The speediest planet is at aphelion on October 8 and greatest eastern elongation on October 26.

Venus passes a mere seven arc minutes south of Regulus on October 3, the closest approach of a planet to a first-magnitude star this year, and six degrees north of the waning crescent Moon on October 6. It is within 2.5 degrees of Regulus from October 1 to October 5 and five degrees of Regulus through October 7. As the month progresses, Venus climbs higher into the sky. Northern hemisphere observers have a more favorable view due to the angle of the ecliptic. By the end of October, Venus rises three hours before the Sun. The most brilliant planet drops slightly in magnitude (-4.1 to -4.0) and apparent size (16 to 13 arc seconds) but grows more gibbous (71 to 80% illuminated) during the course of the month.

Mars travels eastward from Libra into Scorpius on October 6 and into Ophiuchus after the middle of October. Observers in the southern hemisphere are favored. Mars passes between Delta and Beta Scorpii on the nights of October 11 and October 12. The Red Planet lies 3.5 degrees north of the slightly brighter Antares, the “rival of Ares”, on October 20.

Jupiter commences retrograde (i.e., westward) motion towards Aldebaran on October 4. It’s occulted by the Moon, an event not visible from our location, on the next day. Click on http://www.skyandtel...html?page=1&c=y to determine transit times of the central meridian by the Great Red Spot. Data on the Galilean satellites is available at http://www.skyandtel...pt/3307071.html

Saturn is in conjunction with the Sun on October 25.

Uranus spends October retrograding through Pisces. It culminates at midnight. Uranus is located 0.3 degree west-southwest of the sixth-magnitude star 44 Piscium on October 1. By the end of October, the westward motion of the planet increases the separation to 1.5 degrees.

As Neptune retrogrades through Aquarius this month, it is located less than 0.5 degree south of the fifth-magnitude star 38 Capricorni.

Finder charts for Uranus and Neptune can be found at http://media.skyandt...eptune-2012.pdf and page 50 of the September issue of Sky & Telescope.

Pluto is located in northern Sagittarius near the open cluster M25. The dwarf planet is visible shortly after nightfall. Detailed finder charts are available on pages 52 and 53 of the June issue of Sky & Telescope and on page 236 of the RASC Observer’s Handbook 2012.

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

Asteroid 1 Ceres (magnitude 8.5) travels eastward through northeastern Orion and southwestern Gemini this month. It’s occulted by the Moon on October 7 and is stationary on October 31. Asteroid 4 Vesta (magnitude 7.8) heads eastward through Taurus before retrograding. It is stationary on October 21. A finder chart for the two minor planets appears on page 51 of the October issue of Sky & Telescope. During October, asteroid 2 Pallas glides southwestward through western Cetus. Pallas (magnitude 8.3) lies about one degree south-southwest of Iota Ceti (magnitude 3.5) on October 1. The faint asteroids 371 Bohemia, 521 Brixia, and 35 Leukothea occult stars on the morning of October 13, late on the night of October 21, and the evening of October 31 respectively (see page 52 of the October issue of Sky & Telescope). For information on this year’s bright asteroids and upcoming asteroid occultation events respectively, consult http://www.curtrenz.com/asteroids and http://asteroidoccultation.com/

Comet C/2011 F1 (LINEAR) takes a southeastern course through Serpens Caput this month. On October 1, the tenth-magnitude comet is 0.4 degree northeast of the fifth-magnitude star 3 Serpentis. Comet F1 LINEAR lies within two degrees of the bright globular cluster M5 (magnitude 5.7) from October 4 to October 8.

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on October 1, 4, 7, 9, 12, 15, 18, 21, 24, 27, and 30. Consult http://www.skyandtel...a_of_Algol.html for the times of the eclipses. For more on Algol, see http://stars.astro.i.../sow/Algol.html and http://www.solstatio...ars2/algol3.htm

A free star map for October can be downloaded at http://www.skymaps.com/downloads.html

Eighty-five 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 Cephei, 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)

Notable carbon star for October: RZ Pegasi

Seventy-five deep-sky objects for October: NGC 7640, NGC 7662, NGC 7686 (Andromeda); NGC 7180, NGC 7183, NGC 7184, NGC 7293, NGC 7392, NGC 7585, NGC 7606, NGC 7721, NGC 7723, NGC 7727 (Aquarius); Cz43, K12, M52, NGC 7635, NGC 7788, NGC 7789, NGC 7790, St12 (Cassiopeia); B171, B173-4, IC 1454, IC 1470, K10, Mrk50, NGC 7235, NGC 7261, NGC 7354, NGC 7380, NGC 7419, NGC 7510 (Cepheus); IC 1434, IC 5217, NGC 7209, NGC 7223, NGC 7243, NGC 7245 (Lacerta); NGC 7177, NGC 7217, NGC 7320 (the brightest galaxy in Stephan's Quintet), NGC 7331, NGC 7332, NGC 7339, NGC 7448, NGC 7454, NGC 7479, NGC 7619 (the brightest member of Pegasus I), NGC 7626, NGC 7678, NGC 7742, NGC 7769 (Pegasus); NGC 7541, NGC 7562, NGC 7611 (Pisces); IC 5156, IC 5269, IC 5271, NGC 7172, NGC 7173, NGC 7174, NGC 7176, NGC 7201, NGC 7203, NGC 7214, NGC 7221, NGC 7229, NGC 7314, NGC 7361 (Piscis Austrinus); NGC 7507, NGC 7513, NGC 7713, NGC 7755, NGC 7793 (Sculptor)

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

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

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

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*Suggestions for further reading/information:*

Check out the following two sites (both are primarily UK-based) - each of which contain excellent celestial guides for the month ahead:

Astronomical Calendar

Astronomy.co.uk (site includes a short video highlighting some of the main celestial events for the month ahead).