October 2013 Celestial Calendar c/o Dave Mitsky

[Big Dipper]

October 2013 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 Mars is 7 degrees north of the Moon at 6:00; a double Galilean shadow transit begins at 13:43
10/3 Venus is at aphelion today; Uranus (magnitude 5.7, apparent size 3.7") is at opposition at 14:00
10/5 The New Moon (lunation 1123) occurs at 0:34; a double Galilean shadow transit begins at 2:39
10/6 Mercury is 3 degrees south of the Moon at 22:00
10/7 Saturn is 1.9 degrees north of the Moon at 4:00
10/8 The peak of the Draconid meteor shower (10 to 30 per hour) occurs at 8:00; Venus is 5 degrees south of the Moon at 12:00; a double Galilean shadow transit begins at 15:36
10/9 Mercury is at greatest eastern elongation (25 degrees) at 10:00
10/10 Mercury is 5 degrees south of Saturn at 18:00; the Moon is at perigee, subtending 32 arc minutes from a distance of 369,813 kilometers (229,792 miles), at 23:00
10/11 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 19:50; First Quarter Moon occurs at 23:02
10/12 A double Galilean shadow transit begins at 3:25; a rare triple Galilean shadow transit begins at 4:33
10/13 Asteroid 3 Juno is 0.9 degree north of the Moon, with an occultation taking place in far southern South America, the Falkland Islands, and most of Antarctica, at 2:00
10/14 Mars is 1 degree north of first-magnitude star Regulus (Alpha Leonis) at 22:00
10/15 Mercury is at its greatest heliocentric latitude south today; Neptune is 6 degrees south of the Moon at 6:00; a double Galilean shadow transit begins at 17:29
10/16 Venus is 1.6 degrees north of first-magnitude star Antares (Alpha Scorpii) at 15:00
10/17 A double Galilean shadow transit begins at 11:58; Uranus is 3 degrees south of the Moon at 21:00
10/18 A penumbral lunar eclipse begins at 21:50; Full Moon, known as the Blood Moon and this year’s Hunter’s Moon, occurs at 23:38
10/19 A double Galilean shadow transit begins at 6:26
10/21 The peak of the Orionid meteor shower (10 to 20 per hour) occurs at 11:00; Mercury is stationary at 15:00
10/22 A double Galilean shadow transit begins at 19:22
10/24 A double Galilean shadow transit begins at 14:30
10/25 Venus is at its greatest heliocentric latitude south today; the Moon is at apogee, subtending 29 arc minutes from a distance of 404,557 kilometers (251,379 miles), at 14:00; Jupiter is 5 degrees north of the Moon at 22:00
10/26 A double Galilean shadow transit begins at 8:38; Last Quarter Moon occurs at 23:40
10/27 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 22:38
10/29 A double Galilean shadow transit begins at 21:56
10/30 Mars is 6 degrees north of the Moon at 1:00

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. Edwin Hubble discovered Cepheid variable stars in M31 (the Andromeda Galaxy) on October 5, 1923.

The Draconid (formerly the Giacobinid) meteor shower peaks on the morning of October 8. The minor meteor shower known as the Southern Taurids (5 per hour) peaks on the morning of October 10. Despite its name, the radiant is actually in northern Cetus at the shower’s peak. The Orionid meteor shower peaks during the morning of October 21. Unfortunately, a waxing gibbous Moon will compromise this year’s Orionids. Orionid meteors are fragments of Comet 1P/Halley.

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

The Moon is 25.5 days old and is located in Leo on October 1 at 0:00 UT. The Moon reaches its greatest northern declination on October 23 (+19.5 degrees) and its greatest southern declination on October 9 (-19.5 degrees). Longitudinal libration is at a maximum of +5.3 degrees on October 18 and a minimum of -4.8 degrees on October 4 and -5.7 degrees on October 31. Latitudinal libration is at a maximum of +6.9 degrees on October 27 and a minimum of -6.8 degrees on October 13. A slight penumbral lunar eclipse begins at 21:50 UT on October 20 and ends at 1:49 UT. Greatest eclipse occurs at 23:50 UT. Nominal visibility occurs from approximately 23:30 to 0:10 UT. Visit http://saberdoesthestars.wordpress.com/2011/07/05/saber-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-occultations.com/rlo/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 -0.1, 5.9", 73% illuminated, 1.13 a.u., Virgo), Venus (-4.2 magnitude, 18.4", 63% illuminated, 0.91 a.u., Libra), Mars (magnitude 1.6, 4.4", 95% illuminated, 2.14 a.u., Leo), Jupiter (magnitude -2.2, 37.6", 99% illuminated, 5.24 a.u., Gemini), Saturn (magnitude 0.7, 15.5", 100% illuminated, 10.69 a.u., Libra), Uranus (magnitude 5.7, 3.7", 100% illuminated, 19.07 a.u. on October 16, Pisces), Neptune (magnitude 7.9, 2.3", 100% illuminated, 29.33 a.u. on October 16, Aquarius), and Pluto (magnitude 14.1, 0.1", 100% illuminated, 32.75 a.u. on October 16, Sagittarius).

During October evenings, Mercury and Venus 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 northeast, Uranus in the south, and Neptune in the southwest. Mars can be found in the east, Jupiter in the southeast, and Uranus in the west in the morning sky.

At midmonth, Mercury can be seen during evening twilight, Venus sets at 8:00 p.m. local time, Mars rises at 3:00 a.m. local time, Jupiter rises at 11:00 p.m. local time, and Saturn sets at 7:00 p.m. local time for observers at latitude 40 degrees north.

Mercury is situated three degrees south of the waxing crescent Moon on October 6 and five degrees south of Saturn on October 10. The speediest planet is at greatest eastern elongation on October 9 and is at its greatest heliocentric latitude south on October 15. Mercury disappears into the glare of the Sun by month’s end.

As the month progresses, Venus glides eastward through Scorpius. It’s five degrees north of the Moon on October 8. Venus passes within a degree of the second-magnitude star Delta Scorpii on October 9 and 1.6 degrees north of Antares on October 16. The most brilliant of the planets increases in brightness (magnitude -4.2 to magnitude -4.5) and apparent size (18.4 to 24.6 arc seconds) during the course of the month.

Mars travels eastward through western Leo this month. It passes one degree north of the slightly brighter Regulus on October 15. Mars is 6 degrees north of the Moon on October 30 and two degrees south of the spiral galaxies M95 and M96 on October 31.

Jupiter passes six arc minutes due north of the fourth-magnitude star Delta Geminorum on the morning of October 4 and five degrees from the Moon on October 25. Numerous double Galilean shadow transits occur this month. The most favorable ones for North American observers are on the mornings of October 17, October 19, and October 26. A rare triple Galilean shadow transit takes place on October 12. The event, which will last for 65 minutes, begins at 4:32 UT (12:32 a.m. EDT). Callisto’s shadow falls on the disk of Jupiter first, followed by Europa’s, and then Io’s. Callisto’s shadow crosses the south polar region of Jupiter. Another triple shadow transit won’t take place until June3, 2014. Click on http://www.skyandtelescope.com/observing/objects/planets/3304091.html?page=1&... to determine transit times 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 lost in the evening twilight by the end of September.

When it reaches opposition on October 3, Uranus is located 4.8 degrees southwest of the fourth-magnitude star Delta Piscium. At that time, Uranus shines at magnitude 5.7 and subtends 3.7 arc seconds. The gas giant is 2.6 light-hours distant and 3.5 degrees north of the celestial equator. The gap between Uranus and Delta Piscium widens to 5.7 degrees by the end of September.

Neptune lies between the fifth-magnitude stars Sigma and 38 Aquarii early this month. The eighth planet’s retrograde motion places it closer to 38 Aquarii, as September ends.

Finder charts for Uranus and Neptune can be found on page 81 of the August issue of Astronomy, on page 50 of the October issue of Sky & Telescope, and at
http://media.skyandtelescope.com/documents/Uranus-Neptune-2013.pdf

Pluto may still be visible not long after nightfall during the beginning of the month. The dwarf planet is located less than two degrees to the southeast of the open cluster M25 in northern Sagittarius. Detailed finder charts are available on pages 52 and 53 of the June issue of Sky & Telescope, on page 63 of the July issue of Astronomy, and on page 243 of the RASC Observer’s Handbook 2013. Online finder charts are posted at http://dcford.org.uk/findercharts/22pluto_2013_2.pdf and http://britastro.org/computing/ch/_Pluto2013.png

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

Asteroid 42 Isis (magnitude 9.9) is at opposition in Cetus on October 20. Asteroid 20 Massalia (magnitude 8.7) is at opposition in Aries on October 31. The 230-kilometer-wide asteroid 324 Bamberga glides northwestward through Pisces and then heads northeastward towards the fifth-magnitude star Rho Pegasi this month. Asteroid 324 Bamberga shines at magnitude 8.5 on October 1. A finder chart appears on page 51 of the September 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/

During October, Comet C/2012 (ISON) travels southeastward through Leo on a path similar to that of Mars. The comet is just two degrees north of Mars on October 1 and only one degree from October 16 to October 19. It remains within two degrees of Mars through October 23. On the morning of October 15, Comet ISON is 1.1 degrees from Mars while Mars is 0.9 degree from Regulus. Comet ISON passes two degrees north of Regulus on October 16. The comet reaches a greatest solar elongation of 54 degrees on October 23. Comet ISON may brighten to seventh or eighth magnitude by the end of October. An ephemeris is available at http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=CK12S010 and finder charts on page 51 of the October issue of Astronomy and page 50 of the November issue of Sky & Telescope. Consult http://theskylive.com/ison-tracker to learn the comet’s current position and http://www.skyandtelescope.com/community/skyblog/observingblog/Comet-ISON-Upd... for updates on its status. For additional information on comets visible in October, browse http://cometchasing.skyhound.com/ and http://www.aerith.net/comet/future-n.html

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on October 3, 5, 8, 11, 14, 17, 20, 23, 26, and 29. Consult http://www.skyandtelescope.com/observing/objects/variablestars/Minima_of_Algo... for the times of the eclipses. For more on Algol, see http://stars.astro.illinois.edu/sow/Algol.html and http://www.solstation.com/stars2/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).