May Celestial Calendar by Dave Mitsky
All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)
5/1 Mars is 8 degrees north of the Moon at 14:00
5/4 Asteroid 7 Iris (magnitude 9.5) is at opposition at 12:00; the Moon is 1.5 degrees south of the first-magnitude star Spica (Alpha Virginis) at 18:00; Saturn is 6 degrees north of the Moon at 22:00
5/5 May Day or Beltane, a cross-quarter day, occurs at 2:15; Mercury is at its greatest heliocentric latitude south today; the peak of the Eta Aquarid meteor shower (20/hour) occurs at 19:00
5/6 Full Moon, known as the Milk or Planting Moon, occurs at 3:35; the Moon is at perigee, subtending 33 arc minutes from a distance of 356,955 kilometers (221,802 miles), at 4:00
5/9 Pluto is 0.9 degree north of the Moon at 17:00
5/12 Last Quarter Moon occurs at 21:47
5/13 Jupiter is in conjunction with the Sun at 13:00; Neptune is 6 degrees south of the Moon at 22:00
5/14 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to begin at 16:13
5/15 Venus is stationary at 17:00; asteroid 2 Pallas is 0.8 degree north of the Moon, with an occultation occurring in French Polynesia, New Zealand, and part of Antarctica, at 20:00
5/16 Uranus is 6 degrees south of the Moon at 17:00
5/19 The Moon is at apogee, subtending 29 arc minutes from a distance of 406,448 kilometers (252,555 miles), at 16:00
5/20 Asteroid 3 Juno (magnitude 10.2) is at opposition at 0:00; New Moon (lunation 1106) occurs at 23:47; an annular solar eclipse occurs in the eastern Asia, the northern Pacific, and the western United States
5/22 Venus is 5 degrees north of the Moon at 21:00
5/24 Mercury is at the ascending node today
5/27 Mercury is in superior conjunction at 11:00
5/28 The Lunar X (also known as the Werner or Purbach Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to begin at 01:44; First Quarter Moon occurs at 20:16
5/29 Mercury is at perihelion today; Mars is 7 degrees north of the Moon at 11:00
Nicolas Lacaille (1713-1762) and Joseph Lockyer (1836-1920) were born this month.
The peak of the Eta Aquarid meteor shower is severely compromised by moonlight this year. Eta Aquarid meteors are debris from the famous periodic comet 1P/Halley.
The Moon is located in Sextans and is 9.7 days old on May 1 at 0:00 UT. The Moon is at its greatest northern declination on May 22 (+21.7 degrees) and its greatest southern declination on May 8 (-21.7 degrees). Longitudinal libration is at maximum (+7.5 degrees) on May 12 and at minimum (-7.4 degrees) on May 27. Latitudinal libration is at maximum (+6.8 degrees) on May 1 and (+6.9 degrees) on May 28 and at minimum (-6.8 degrees) on May 13. The largest Full Moon of 2012 occurs on May 6. Large tides will take place from May 6 through May 9. A difficult-to-observe occultation of the third-magnitude star Zeta Tauri by a very young Moon takes place in much of the western United States on May 22. See http://www.lunar-occ...ota/iotandx.htm for additional information on lunar occultations. 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 this month are available at http://www.lunar-occ...o/rays/rays.htm
The Sun is located in Aries on May 1. The first solar eclipse of 2012 takes place on May 20. An annular solar eclipse, the fifty-eighth eclipse of Saros 128, can be seen from eastern Asia, the northern Pacific, and the western United States and a partial eclipse from most of Asia, the Pacific, and the western two-thirds of North America. Greatest eclipse occurs at 23:52:47 UT, at which time the duration of annularity will be five minutes and forth-six seconds. For further information on this event, consult http://eclipse.gsfc....12/ASE2012.html and pages 50 and 51 of the May issue of Sky & Telescope.
Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on May 1: Mercury (magnitude -0.1, 6.4", 64% illuminated, 1.04 a.u., Pisces), Venus (magnitude -4.7, 37.4", 27% illuminated, 0.45 a.u., Taurus), Mars (magnitude 0.0, 9.9", 91% illuminated, 0.94 a.u., Leo), Jupiter (magnitude -2.0, 32.9", 100% illuminated, 5.99 a.u., Aries), Saturn (magnitude 0.3, 19.0", 100% illuminated, 8.76 a.u., Virgo), Uranus (magnitude 5.9, 3.4", 100% illuminated, 20.89 a.u., Pisces), Neptune (magnitude 7.9, 2.3", 100% illuminated, 30.36 a.u., Aquarius), and Pluto (magnitude 14.0, 0.1", 100% illuminated, 31.68 a.u., Sagittarius).
In the evening, Venus is the northwest, Mars is the southwest, and Saturn is in the southeast. Mars is in the west and Saturn in the south at midnight. Mercury and Uranus can be found in the east and Neptune in southeast at dawn.
Venus sets at 11:00 p.m. local daylight time. Mars sets at 3:00 a.m. local daylight time. Saturn transits at 11:00 p.m. and sets at 5:00 a.m. local time at midmonth, for observers at latitude 40 degrees north.
Mercury reaches superior conjunction on May 27. This apparition favors southern hemisphere observers. The speedy planet brightens from magnitude -0.1 to magnitude -1.5, as it decreases in apparent size from 6.4 to 5.2 arc seconds.
Venus shines at its maximum brilliance early this month. It sets 3.5 hours after the Sun. Venus continues to decline in phase and ends the month less than one per cent illuminated. However, it swells to almost one arc minute in apparent size by that time. Venus is 0.8 degree south of the second-magnitude star Alnath (Beta Tauri) on May 6. A thin crescent Moon passes five degrees south of Venus on the evening of May 22.
Mars begins the month at magnitude 0.0 but fades to magnitude 0.5 by the end of May. It shrinks 20% in apparent size during the course of the month. The Red Planet is six degrees east of the first-magnitude star Regulus (Alpha Leonis) on May 1 but finishes May almost fifteen degrees to the southeast of Leo’s lucida. Mars is more than one astronomical unit from the Earth on May 8.
Jupiter is in conjunction with the Sun on May 13 and, as a result, is not visible this month.
Saturn decreases in brightness from magnitude 0.3 to magnitude 0.5. During May, Saturn’s ring plane is inclined by 13 degrees. Its rings subtend 43 arc seconds. As Saturn retrogrades through Virgo, it remains within five degrees of the first-magnitude star Spica for the entire month. Eighth-magnitude Titan is due south of Saturn on the evenings of May 4 and May 20. Saturn’s brightest satellite is due north of the planet on the evenings of May 12 and May 28. Prior to midnight on May 14, eleventh-magnitude Iapetus is two arc minutes north of Saturn. A star of similar brightness, GSC 4972:631, is situated between Iapetus and Saturn. For further information on Saturn’s satellites, browse http://www.skyandtel...pt/3308506.html
Uranus rises shortly before 3:00 a.m. local daylight time. It travels from Cetus to Pisces during May and can be found one degree northeast of the sixth-magnitude star 44 Piscium by the end of the month.
Neptune is observable during morning twilight by the middle of May. It lies approximately three degrees south of the fourth-magnitude star Theta Aquarii and two degrees east of the fifth-magnitude star e Aquarii (38 Aquarii). Nereid, Neptune’s third-largest satellite, was discovered on May 1, 1949 by Gerard Kuiper.
Pluto lies in northern Sagittarius, less than two degrees east of the open cluster M25. The fourteen-magnitude dwarf planet can be found one half of a degree east of the seventh-magnitude star SAO 161665 on May 1 and just three arc minutes south of that same star on the morning of May 31.
Comet C/2009 P1 (Garradd) dims to tenth-magnitude this month as it passes from Lynx into Cancer. It lies than one degree west of the tenth-magnitude spiral galaxy NGC 2683 on the evenings of May 10 and May 11. On the evenings of May 24 and May 25, the comet passes between the fifth-magnitude stars Rho1 and Rho2 Cancri. Visit http://cometchasing.skyhound.com/ for additional information on this and other comets visible during May.
Asteroid 5 Astraea shines at magnitude 10.9 as it travels southeastward through Leo and Virgo during May. This small main-belt asteroid passes one half of a degree south of the fifth-magnitude star Iota Leonis on the nights of May 11 and May 12 and one half of a degree northwest of the fifth-magnitude star Omega Virginis on the night of May 31. Data on asteroid occultations taking place in May is available at http://www.asteroido.../2012_05_si.htm
During May, nine stars (Capella, Pollux, Procyon, Regulus, Spica, Arcturus, Antares, Vega, and Deneb) and three planets (Venus, Mars, and Saturn) with magnitudes brighter than 1.5 are visible in the early part of the night.
A free star map for May can be downloaded at http://www.skymaps.com/downloads.html
The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on May 2, 5, 8, 11, 13, 16, 19, 22, 25, 28, and 31. For more on Algol, see http://stars.astro.i.../sow/Algol.html and http://www.solstatio...ars2/algol3.htm
Eighty binary and multiple stars for May: 1 Bootis, Struve 1782, Tau Bootis, Struve 1785, Struve 1812 (Bootes); 2 Canum Venaticorum, Struve 1624, Struve 1632, Struve 1642, Struve 1645, 7 Canum Venaticorum, Alpha Canum Venaticorum (Cor Caroli), h2639, Struve 1723, 17 Canum Venaticorum, Otto Struve 261, Struve 1730, Struve 1555, h1234, 25 Canum Venaticorum, Struve 1769, Struve 1783, h1244 (Canes Venatici); 2 Comae Berenices, Struve 1615, Otto Struve 245, Struve 1633, 12 Comae Berenices, Struve 1639, 24 Comae Berenices, Otto Struve 253, Struve 1678, 30 Comae Berenices, Struve 1684, Struve 1685, 35 Comae Berenices, Burnham 112, h220, Struve 1722, Beta Comae Berenices, Burnham 800, Otto Struve 266, Struve 1748 (Coma Berenices); h4481, h4489, Struve 1604, Delta Corvi, Burnham 28, h1218, Struve 1669 (Corvus); H N 69, h4556 (Hydra); Otto Struve 244, Struve 1600, Struve 1695, Zeta Ursae Majoris (Mizar), Struve 1770, Struve 1795, Struve 1831 (Ursa Major); Struve 1616, Struve 1627, 17 Virginis, Struve 1648, Struve 1658, Struve 1677, Struve 1682, Struve 1689, Struve 1690, 44 Virginis, Struve 1719, Theta Virginis, 54 Virginis, Struve 1738, Struve 1740, Struve 1751, 81 Virginis, Struve 1764, Struve 1775, 84 Virginis, Struve 1788 (Virgo)
Notable carbon star for May: SS Virginis
One hundred and sixty-five deep-sky objects for May: NGC 5248 (Bootes); M3, M51, M63, M94, M106, NGC 4111, NGC 4138, NGC 4143, NGC 4151, NGC 4214, NGC 4217, NGC 4244, NGC 4346, NGC 4369, NGC 4449, NGC 4485, NGC 4490, NGC 4618, NGC 4631, NGC 4656, NGC 4868, NGC 5005, NGC 5033, NGC 5297, NGC 5353, NGC 5354, Up 1 (Canes Venatici); Mel 111, M53, M64, M85, M88, M91, M98, M99, M100, NGC 4064, NGC 4150, NGC 4203, NGC 4212, NGC 4251, NGC 4274, NGC 4278, NGC 4293, NGC 4298, NGC 4302, NGC 4314, NGC 4350, NGC 4414, NGC 4419, NGC 4448, NGC 4450, NGC 4459, NGC 4473, NGC 4474, NGC 4494, NGC 4559, NGC 4565, NGC 4651, NGC 4689, NGC 4710, NGC 4725, NGC 4874, NGC 5053 (Coma Berenices); NGC 4027, NGC 4038-9, NGC 4361 (Corvus); M68, M83, NGC 4105, NGC 4106, NGC 5061, NGC 5101, NGC 5135 (Hydra); M40, NGC 4036, NGC 4041, NGC 4051, NGC 4062, NGC 4085, NGC 4088, NGC 4096, NGC 4100, NGC 4144, NGC 4157, NGC 4605, NGC 5308, NGC 5322 (Ursa Major); M49, M58, M59, M60, M61, M84, M86, M87, M89, M90, M104, NGC 4030, NGC 4073, NGC 4168, NGC 4179, NGC 4206, NGC 4215, NGC 4216, NGC 4224, NGC 4235, NGC 4260, NGC 4261, NGC 4267, NGC 4281, NGC 4339, NGC 4343, NGC 4365, NGC 4371, NGC 4378, NGC 4380, NGC 4387, NGC 4388, NGC 4402, NGC 4429, NGC 4435, NGC 4438, NGC 4517, NGC 4526, NGC 4535, NGC 4536, NGC 4546, NGC 4550, NGC 4551, NGC 4567, NGC 4568, NGC 4570, NGC 4593, NGC 4596, NGC 4636, NGC 4638, NGC 4639, NGC 4643, NGC 4654, NGC 4666, NGC 4697, NGC 4698, NGC 4699, NGC 4753, NGC 4754, NGC 4760, NGC 4762, NGC 4866, NGC 4900, NGC 4958, NGC 5044, NGC 5054, NGC 5068, NGC 5077, NGC 5084, NGC 5087, NGC 5147, NGC 5170, NGC 5247, NGC 5363, NGC 5364 (Virgo)
Top ten deep-sky objects for May: M3, M51, M63, M64, M83, M87, M104, M106, NGC 4449, NGC 4565
Top ten deep-sky binocular objects for May: M3, M51, M63, M64, M84, M86, M87, M104, M106, Mel 111
Challenge deep-sky object for May: 3C 273 (Virgo)
The objects listed above are located between 12:00 and 14:00 hours of right ascension.
May 2012 Celestial Calendar
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