May Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract 4 hours and, when appropriate, 1 calendar day for EDT)

5/1 May Day or Beltane, a cross-quarter day; a maximum lunar libration of 9.0 degrees occurs at 16:00
5/2 Mars is 3.5 degrees south of the Moon at 11:00
5/3 Asteroid 2 Pallas is stationary at 3:00; the Moon is 1.7 degrees north of asteroid 4 Vesta at 7:00; the Moon is 1.8 degrees south-southwest of the first magnitude star Pollux at 11:00
5/4 Saturn is 3.7 degrees south-southwest of the Moon at 11:00; Jupiter is at opposition at 15:00; the Moon is 2.8 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster) at 15:00
5/5 The peak of the Eta Aquarid meteor shower (10/hour for northern hemisphere observers) occurs at 5:00; First Quarter Moon occurs at 5:13
5/6 Astronomy Day takes place in the United States; the Moon is 2.4 degrees north-northeast of the first magnitude star Regulus at 13:00
5/7 The Moon is at apogee, subtending 29'32" from a distance of 404,572 km, at 7:00
5/8 The C fragment of Comet 73P/Schwassmann-Wachmann 3 is within a few arcminutes of the planetary nebula M57 (the Ring Nebula) at 3:00; a minimum lunar libration of 1.4 degrees occurs at 15:00
5/9 The Moon is at the descending node (longitude 183.6 degrees) at 8:30
5/10 Neptune is at western quadrature at 14:00
5/11 The Moon is 0.28 degree north of the first magnitude star Spica at 1:00 - an occultation occurs in portions of central and west Africa and eastern North America
5/12 Jupiter is 4.6 degrees south-southwest of the Moon at 13:00
5/13 Full Moon, known as the Milk or Planting Moon, occurs at 6:51; the periodic comet 73P/Schwassmann-Wachmann 3 is closest to the Earth at 7:00
5/14 The Sun enters the constellation of Taurus (ecliptic longitude 53.29 degrees) at 5:00; the equation of time equals 3.67 minutes at 7:00; the Moon is 0.29 degree southeast of the first magnitude star Antares at 15:00 - an occultation occurs in New Zealand, Australia, and Indonesia
5/15 Mars and Neptune are at heliocentric opposition (longitudes 137.9 and 317.9 respectively); a maximum lunar libration of 8.3 degrees occurs at 15:00
5/17 Venus is at aphelion at 3:00; Mercury is at the ascending node at 7:00
5/18 Mercury is in superior conjunction with the Sun at 20:00
5/19 Mars is at its greatest latitude north of the ecliptic plane at 3:00; Neptune is 3.3 degrees north-northwest of the Moon at 18:00
5/20 Mercury is 3.6 degrees south-southeast of the center of the bright open cluster M45 (the Pleiades) at 1:00; Last Quarter Moon occurs at 9:21
5/21 Uranus is 0.85 degree north-northwest of the Moon at 11:00 - an occultation occurs in the southwestern portion of southern Africa and most of Antarctica; Mercury is at perihelion at 23:00
5/22 Neptune is stationary in right ascension at 14:00; a minimum lunar libration of 0.5 degree occurs at 14:00; the Moon is at perigee, subtending 32'25" from a distance of 368,609 km, at 15:00; the Moon is at the ascending node (longitude 2.7 degrees) at 18:02
5/23 Jupiter's four Galilean satellites form two interesting pairs (Io and Europa comprising one pair and Ganymede and Callisto the other) to the east of Jupiter at 0:00; Mars (magnitude 1.6) is 5.2 degrees south of Pollux (magnitude 1.2) at 13:00
5/24 Venus is 3.8 degrees south-southeast of the Moon at 5:00
5/25 Mars is 5 degrees south of Pollux at 5:00
5/26 The Moon is 0.36 degree northeast of the center of M45 at 20:00
5/27 New Moon (lunation 1032) occurs at 5:26
5/28 Mercury is 3.2 degrees south of the Moon at 2:00
5/29 Ganymede reappears from occultation at 2:50 and disappears into eclipse at 3:23
5/30 The Moon is 2.0 degrees south of Pollux at 20:00
5/31 Mars is 3.1 degrees south-southwest of the Moon at 5:00; the Moon is 0.83 degree north-northeast of Vesta at 12:00 - an occultation occurs in northern Europe, northern North America, Japan, and eastern Asia; Saturn is 3.4 degrees south-southwest of the Moon at 23:00; the Moon is 2.5 degrees north-northeast of M44

The Moon is at its greatest northern declination on May 1 and May 29 and its greatest southern declination on May 16. 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 planets on May 1: Mercury (-0.6 magnitude, 5.6", 80% illuminated), Venus (-4.2 magnitude, 17.3", 66% illuminated), Mars (1.5 magnitude, 4.9", 93% illuminated), Jupiter (-2.5 magnitude, 44.6", 100% illuminated), Saturn (0.3 magnitude, 18.0", 100% illuminated), Uranus (5.9 magnitude, 3.4", 100% illuminated), Neptune (7.9 magnitude, 2.2", 100% illuminated), and Pluto (13.9 magnitude, 0.1", 100% illuminated).

Morning planets: Mercury, Venus, Uranus, Neptune, and Pluto

Evening planets: Mars, Jupiter, and Saturn

Mercury can be seen very low in the west-northwest about an hour after sunset during the final days of May.

Venus continues to wax in phase and wane in diameter as it rises not quite two hours before the Sun. By month's end, Venus is three quarters illuminated and about 14 arcminutes in apparent size.

Mars begins the month less than a degree from Epsilon Geminorum and about 25 degrees from Saturn. Mars and Saturn are separated by nine degrees on May 30.

Jupiter, which lies to the north of Zubenelgenubi (Alpha Librae), is at its best this month. It rises at sunset and sets at sunrise when it reaches opposition on May 4. Red Spot Junior, Jupiter's new red spot, lags behind the Great Red Spot (GRS) by about an hour. In order to determine transit times for the GRS, click on http://skyandtelescope.com/observing...icle_107_1.asp

Residing in Cancer, Saturn sets less than four hours after sunset by the end of May. The ringed planet is about two degrees to the west of M44 at the beginning of the month and ends May quite close to the open cluster. Around the third week of the month, Saturn's unusual moon Iapetus is located about 10 ring diameters to the west of Saturn and shines at tenth magnitude.

Uranus is less than one arcminute distant from 81 Aquarii on the morning of May 3. Both Uranus and Neptune can be seen low in the southeast before sunrise.

Pluto is located about three hours to the east of Jupiter in Serpens Cauda. It is best positioned for observing after midnight.

The fractured periodic comet 73P/Schwassmann-Wachmann 3 travels from Hercules to Cetus during the course of the month. On May 12, fragment C, the brightest of some forty pieces, passes by the Earth at a distance of approximately 11,000,000 kilometers (0.079 a.u.), the closest approach to the Earth by a comet since 1983. Fragment C may glow at fourth magnitude, bright enough to be seen without optical aid, and may be rather diffuse and large in apparent size. The comet will move about six degrees a day during the time of its closest approach. Unfortunately, bright moonlight will spoil the view during this period. The comet is lost in the glare of sunrise by the end of the month.

Comet C/2006 A1 (Pojmanski) passes to the west of Cassiopeia during May. It is growing rather dim and is predicted to be fainter than thirteenth magnitude by month's end.

CometC/2004 B1 (LINEAR) glides northwestward through Aquila into Ophiuchus this month. The tenth magnitude fuzzball passes close by NGC 6781, a planetary nebula in northern Aquila, on the morning of May 9.

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, Oto 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)

Challenge binary star for May: 48 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)

Challenge deep-sky object for May: 3C 273 (Virgo)

__________________
Chance favors the prepared mind.
De gustibus non est disputandum.
Never attribute to malice that which can be adequately explained by stupidity.

Thanks for doing this Dave, *I* find it a useful resource, and I'm sure a lot of other people do too (including, I'll bet, Kaptain K).

__________________
Forming opinions as we speak

I'd like to second that and use the short time this thread is open to give you many, many thanks for the work you invest into this.

Keep it up, Dave!

__________________
Non sunt multiplicanda entia praeter necessitatem.

For your hard work. We all appreciate it very much.

__________________
Time is a great teacher, but unfortunately it kills all its pupils - Berlioz

Orion 8" F 4.9 Newt on an LXD75 Go-to mount

Telrad
Televue Plossl 8mm/20mm
UO Abbe Ortho
Baader Hyperion 13mm/17mm/24mm
Orion Q70 26mm
Takahashi LE 5mm
Vixen LVW 22mm
Paracorr
Orion SSDS Monochrome Imager II on the way!