October Calendar by Dave Mitsky
All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)
10/1 The New Moon (lunation 1160) occurs at 0:11
10/2 The Moon is 5.5 degrees north-northeast of the first magnitude star Spica (Alpha Virginis) at 7:00
10/3 Mars is at its greatest heliocentric ecliptic latitude south (-1.8 degrees) at 3:00; Venus is 4.9 degrees south-southwest of the Moon at 20:00
10/4 The Moon is at apogee at a distance of 406,096 kilometers (252,336 miles) at 11:03
10/8 Fall Astronomy Day occurs today; the peak of the Draconid meteor shower (10 to 30 per hour) occurs at 2:00; asteroid 2 Pallas is stationary at 2:00; 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 12:24; Mercury is at its greatest heliocentric ecliptic latitude north (+7.0 degrees) at 20:00
10/9 First Quarter Moon occurs at 4:33
10/11 Mercury (magnitude -1.1) is 0.79 degree north of Jupiter (magnitude -1.7) at 10:00
10/13 Neptune is 1.2 degrees south of the Moon, with an occultation taking place in northwest Canada, Alaska, and easternmost Russia, at 6:00; the Moon is at the descending node at 9:43
10/15 Uranus (magnitude +5.7, apparent size 3.7") is at opposition at 11:00
10/16 Uranus is 2.7 degrees north-northwest of the Moon at 3:00; Full Moon, known as the Blood Moon and this year’s Hunter’s Moon, occurs at 4:23; the Moon is at perigee at a distance of 357,861 kilometers (222,364 miles) at 23:34
10/18 The Moon is 9.1 degrees south of the bright open cluster M45 (the Pleiades) in Taurus at 15:00
10/19 The Moon is 0.3 degree north of the first-magnitude star Aldebaran (Alpha Tauri), with an occultation taking place in southern Europe, the eastern United States, southeast Canada, Central America, and Mexico, at 7:00; Mars is 3.3 degrees south of Pluto at 14:00
10/20 The Moon is 5.7 degrees south of the bright open cluster M35 in Gemini at 20:00
10/21 The peak of the Orionid meteor shower (15 per hour) occurs at 5:00; asteroid 1 Ceres (magnitude +7.4) is at opposition at 5:00
10/22 Last Quarter Moon occurs at 20:04
10/23 Asteroid 18 Melpomene (magnitude +8.0) is at opposition at 13:00
10/24 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 14:08
10/25 The Moon is 1.6 degrees south of the first-magnitude star Regulus (Alpha Leonis) at 16:53
10/26 The Moon is at the ascending node at 1:44; Venus is 3 degrees north of the first-magnitude star Antares (Alpha Scorpii) at 4:00
10/27 Mercury is in superior conjunction with the Sun at 16:00
10/28 Jupiter is 1.4 degrees north of the Moon at 13:42
10/29 Mars is at perihelion (1.24 astronomical units from the Sun) at 13:00
10/30 The New Moon (lunation 1161) occurs at 17:38; Saturn (magnitude +0.6) is 3 degrees north of Venus (magnitude -4.0) at 19:00
10/31 Venus is at aphelion (0.73 astronomical units from the Sun) at 9:00; the Moon is at apogee at a distance of 406,662 kilometers (252,688 miles) at 19:29
Ejnar Hertzsprung and Henry Norris Russell were born this month.
The first recorded solar eclipse took place on October 22, 2136 B.C. Giovanni Cassini discovered Saturn’s odd satellite Iapetus on October 25, 1671. William Lassell discovered Triton, Neptune’s brightest satellite, on October 10, 1846. Two of the satellites of Uranus, Ariel and Umbriel, were discovered by William Lassell on October 24, 1851. 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 evening of October 7th. A waxing crescent Moon will interfere with observing this shower. The Draconids are quite variable and have produced meteor storms in 1933 and 1946. Comet 21P/Giacobini-Zimmer is the parent comet of the Draconids. Consult http://earthsky.org/...d-meteor-shower for additional information on the Draconid meteor shower. The Southern Taurid shower, debris from Comet 2P/Encke, may produce five meteors per hour when it peaks on October 10th. The Orionid meteor shower peaks on the night of October 21st. A waning gibbous Moon will adversely affect viewing the shower during the morning hours of October 22nd. Orionid meteors are fragments of Comet 1P/Halley. Browse http://www.timeandda...er/orionid.html or http://earthsky.org/...d-meteor-shower for more on the Orionids.
Information on Iridium flares and passes of the ISS, the Tiangong-1, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/
During the first and last weeks of the month, the zodiacal light may be visible in the pre-dawn eastern sky from a dark site. Articles on the zodiacal light appear at http://www.atoptics....ighsky/zod1.htm and http://earthsky.org/...t-or-false-dawn
The Moon is 29.6 days old, subtends 29.6 arc minutes, is illuminated 0.0%, and is located in Virgo on October 1st at 0:00 UT. New Moon occurs twice this month, on October 1st and October 30th. Large tides occur on October 17th, 18th, 19th, and 20th. The farthest lunar apogee of the year takes place on October 31st. The Moon reaches its greatest northern declination on October 21st (+18.6 degrees) and its greatest southern declination on October 8th (-18.5 degrees). Longitudinal libration is at a maximum of +7.8 degrees on October 23rd and a minimum of -7.2 degrees on October 11th. Latitudinal libration is at a maximum of +6.6 degrees on October 19th and a minimum of -6.8 degrees on October 6th. The waning gibbous Moon occults Aldebaran on the night of October 18th/19th. A grazing occultation will take place in certain parts of the United States and Canada. Theta 1(magnitude +3.8) and Theta 2 (magnitude +3.4) Tauri in the bright open cluster Melotte 25 (the Hyades) will be occulted prior to Aldebaran and will reappear about 11:00 p.m. EDT. Some two hours later Aldebaran will disappear for an hour or more. For further information on the event, consult http://www.lunar-occ...r/1019zc692.htm or page 49 of the October issue of Sky & Telescope. 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 1st at 0:00 UT. It enters Libra at 18:00 UT on October 30th.
Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on October 1st: Mercury (magnitude -0.8, 6.6", 60%, 1.02 a.u., Leo), Venus (magnitude -3.9, 12.1", 85%, 1.38 a.u., Libra), Mars (magnitude +0.1, 8.8", 85%, 1.07 a.u., Sagittarius), Jupiter (magnitude -1.7, 30.6", 100%, 6.45 a.u., Virgo), Saturn (magnitude +0.5, 15.9", 100%, 10.45 a.u., Ophiuchus), Uranus (magnitude +5.7, 3.7", 100%, 18.95 a.u. on October 16th, Pisces), Neptune (magnitude +7.8, 2.3", 100%, 29.22 a.u. on October 16th, Aquarius), and Pluto (magnitude +14.2, 0.1", 100%, 33.32 a.u. on October 16th, Sagittarius).
During October evenings, Venus and Saturn are in the southwest, Mars is in the south, Uranus is in the east, and Neptune is in the southeast. At midnight, Uranus is located in the south and Neptune in the southwest. Mercury and Jupiter can be found in the east and Uranus in the west in the morning sky.
For observers at latitude 40 degrees north at midmonth, Mercury is visible during morning twilight, Venus sets at 8:00 p.m. local time, Mars sets at 11:00 p.m. local time, Jupiter rises at 6:00 a.m. local time, and Saturn sets at 9:00 p.m. local time.
Mercury is visible in the morning sky in during the first half of October. Mercury is at its greatest heliocentric latitude north on October 8th and is in a daytime conjunction with Jupiter on October 11th. The speediest planet is in superior conjunction with the Sun on October 27th. Mercury decreases from 6.6 arc seconds to 4.7 arc seconds in apparent size but increases in illumination from 60% to 100% this month.
During October, the apparent diameter of Venus increases from 12.1 to 13.9 arc seconds while it decreases in phase from 85 to 78%. The brightest of the planets enters Scorpius on October 17th and Ophiuchus on October 24th. Venus is three degrees north of Antares on October 25th and three degrees south of Saturn on October 30th. It is at aphelion on October 31st.
Mars has a number of close encounters with globular clusters this month. It is located 0.8 degree south of the seventh-magnitude globular cluster M28 on October 5th and 0.2 degree south of the third-magnitude star Lambda Sagittarii on October 6th. On October 7th, the Red Planet appears just four arc minutes south of the ninth-magnitude globular cluster NGC 6638. Mars passes 1.6 degrees south of the fifth-magnitude globular cluster M22 on October 9th. The Red Planet is at its greatest southern heliocentric latitude on October 3rd. Mars is at perihelion on October 29th.
Jupiter reappears low in the morning sky by the middle of October. It is located 1.4 degrees south of the Moon on October 28th. Jupiter rises nearly 2.5 hours before the Sun by the end of the month.
Saturn sets in the late evening. Its disk spans 16 arc seconds and its rings 35 arc seconds in mid-October. The ring tilt angle is 26 degrees. Saturn, Venus, and Antares form a nearly vertical line seven degrees in length low in the southwest on October 27th. Eighth-magnitude Titan is due south of the planet on October 2nd and October 18th and north of it on October 11th and October 27th. For information on Saturn’s major satellites, browse http://www.skyandtel...watching-tools/
Uranus reaches opposition on October 15th. At that time, the seventh planet is located at declination +8.2 degrees, shines at magnitude +5.7, subtends 3.7 arc seconds, and is 2.6 light-hours (2.9 billion kilometers or 1.8 billion miles) from the Earth. Uranus is located roughly halfway between the two fifth-magnitude stars Zeta and Mu Piscium when it is at opposition.
Neptune continues to retrograde through Aquarius. In the early part of the month, Neptune lies two degrees southeast of the fourth-magnitude star Lambda Aquarii. The eighth planet is 2.5 degrees from that star and 0.1 degree north of two ninth-magnitude stars by the final week of October.
Finder charts for Uranus and Neptune appear on page 50 of the October issue of Sky & Telescope. Online finder charts for the two planets can be found at http://www.nakedeyep....com/uranus.htm and http://www.nakedeyep...com/neptune.htm and also at http://www.skyandtel...p16_Finders.pdf
The dwarf planet Pluto is located 0.3 degree northwest of the fourth-magnitude star Omicron Sagittarii during the last week of October. It passes four arc minutes due north of a seventh-magnitude star on October 27th and only eight arc seconds north of a ninth-magnitude star on October 30th. Articles on locating and observing Pluto are available on pages 48 and 49 of the July issue of Sky & Telescope and pages 64 and 65 of the July issue of Astronomy and a finder chart appears online at http://www.bluewater.../Pluto-2016.jpg
For more on the planets and how to locate them, see http://www.nakedeyeplanets.com/
During October, the periodic comet 43P/Wolf-Harrington glides southeastward near the borders of Hydra, Leo, and Sextans. The eleventh-magnitude comet passes between the twelfth-magnitude galaxy NGC 2962 and the sixth-magnitude star 2 Hydrae on October 5th. For additional information on comets visible in October, browse http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html
Asteroid 11 Parthenope shines at ninth magnitude as it travels southwestward from Cetus into Pisces this month. It passes less than two degrees south of 12 Ceti (magnitude +3.5) on October 4th and 5th. Asteroid 1 Ceres (magnitude +7.4) is at opposition on October 21st. Asteroid 18 Melpomene (magnitude +8.0) is at opposition on October 23rd. Browse https://in-the-sky.o...20161021_14_100 and https://in-the-sky.o...20161022_15_100 respectively for finder charts and additional information. Other asteroids brighter than magnitude +11.0 reaching opposition this month include 51 Nemausa (magnitude +10.6) on October 13th, 57 Mnemosyne (magnitude +10.7) on October 19th, and 444 Gyptis (magnitude +10.7) on Oct 26th. For information on this year’s bright asteroids and upcoming asteroid occultation events respectively, consult http://www.curtrenz.com/asteroids.html and http://asteroidoccultation.com/
The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from +2.1 to +3.4, on October 2nd, 5th, 8th, 11th, 14th, 17th, 19th, 22nd, 25th, 28th, and 31st. Consult http://www.skyandtel...watching-tools/ and page 51 of the October issue of Sky & Telescope 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
The long-period variable star Mira (Omicron Ceti) may reach a minimum of magnitude +9.4 sometime in late October. For further details see page 49 of the October issue of Sky & Telescope. Browse http://earthsky.org/...quite-wonderful and http://www.daviddarl...dia/M/Mira.html for more on Mira the Wonderful.
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.