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The Skies of May, 2023

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May Skies

by Dick Cookman

May 3, 2023

Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, May Moon

Focus Constellations: Ursa Major, Ursa Minor, Draco, Cepheus, Cassiopeia, Camelopardalis, Lynx, Cancer, Leo, Leo Minor, Virgo, Coma Berenices, Bootes, Hercules, Lyra, Cygnus

Comet Journals

There are no bright comets in May. C/2020 V2 (ZTF) has faded to 11th magnitude and is joined by 11th magnitude Comet C/2021 T4 Lemmon which may approach naked eye visibility in July. The former is an Oort Belt object and is currently in Aries. It will dive into southern hemisphere skies this summer when it may brighten to 9th magnitude. It will pass perihelion on May 8 and be closest to Earth in September. The latter is another Oort Belt comet. It is in Cetus in southern hemisphere skies where it will be closest to Earth on July 20 and then pass perihelion on the 31st. It will enter northern hemisphere skies at the end of the year as it retreats into the distant yonder.

Mars Landers

In early March, NASA’s Perseverance rover ascended through the layers exposed on the edge of a delta extending five kilometers into Jezero Crater from its margin. The delta is at the mouth of a dried up canyon carved by an ancient river which flowed into a lake which once filled Jezero Crater. The course of this river valley can be traced to highlands over 50 kilometers distant. In March and April, the rover traversed almost four kilometers from the edge of the delta, circuited around Belva Crater, which was formed by post delta impact, and is now approaching Neretva Vallis, the canyon which fed the delta. The delta caprock includes boulders and flagstones which probably originated from sediment and rocks carried from upstream and debris which rained down from surrounding impacts.

Meteor Showers

Dark skies unpolluted by unshielded outdoor lighting offer one major shower in May when the Earth visits the debris field left from previous passages of the most famous comet:

  • May 6: Eta Aquarids Active Apr 19-May 28. Radiant 22h32m -01°. ZHR ~40. 66 km/sec. 1 day after New Moon. Progenitor: Comet 1P/Halley

Planet Plottings

Galileo Galilei, an Italian polymath who has been called the father of observational astronomy, modern-era classical physics, the scientific method, and modern science, studied motion, developed the pre-Einstein theory of relativity which provided a basis for the future work of Newton, and invented a variety of scientific instruments. After hearing about a viewing device developed in Holland, he designed and marketed working telescopes which he sold to fund his daughter’s dowries. He utilized his telescopes to examine the phases of Venus, Jupiter’s 4 largest moons, Saturn’s rings, lunar craters, and sunspots. The resulting observational evidence led him to promote the Copernican model of a Sun centered solar system and attempt its incorporation into Church doctrine. His ideas were investigated and rejected by the Roman Inquisition. Galileo’s subsequent defense (Dialogue of the Two Chief World Systems), alienated the Pope and Jesuits. He was convicted of heresy and sentenced to lifelong house arrest.

Saturn (1.0) in Aquarius and Neptune (7.9) in Pisces are morning planets. A waning crescent Moon passes Saturn on the 13th and Neptune on the 14th. Jupiter (-1.9) in Pisces is visible on the eastern horizon right before sunrise and Mercury (6.0) in Aries, is at inferior conjunction on May 1. Mercury is best viewed at magnitude 0.6 when below and slightly south of Jupiter at greatest western elongation on the 29th. A waning crescent Moon passes Jupiter and Mercury in the evening of May 17, after the morning New Moon. Uranus (5.8) in Aries is at Solar conjunction on the 9th and not visible in May.

May is the best month in 2023 to view Venus (-4.0 to -4.2) which moves along the northwestern evening horizon from between the horns of Taurus on the 1st into Gemini on the 8th. The waxing crescent Moon passes within 2° of Venus on the 23rd. Mars (1.3 to 1.5) is south of Venus in Gemini and moves into Cancer by the 17th. It is orbiting the Sun about 90° behind Earth and is farthest from the Sun (aphelion) on the 30th. The waxing crescent Moon passes Mars on the 24th.

PlanetConstellation(s)MagnitudePlanet PassagesTimeDate
SunAries-26.5New Moon11:53AM EDT5/19
MercuryAries6.0 to 0.6Inferior Conjunction
Max. West Elongation
7:00PM EDT
2:00AM EDT
VenusTaurus, Gemini-4.0 to -4.2   
MarsGemini – Cancer1.3 to 1.6   
UranusAries5.9 to 5.8Solar Conjunction4:00PM EDT5/9

May Moon

The New Moon of May is in Taurus on the 19th at 11:53AM EDT. The New Moon marks the start of Lunation 1242 which ends 29.53 days later with the New Moon of June in Taurus on the 18th at 12:37AM EDT. The Full Moon is in Libra on the 5th at 1:34PM EST. The May Moon is called the “Planting Moon” or the “Milk Moon”. It was called the “Hare Moon” in Medieval England and for Celts it was the “Bright Moon”. In China, it is the “Dragon Moon” and Colonial Americans called it “Milk Moon”. Anishnaabe (Odawa and Ojibwe) first people recognize the 5th Moon of the year as the Flower Moon and as “Namebine-giizis” (Suckerfish Moon) in the western dialect and “Zaagibagaa-giizis” (Budding Moon) in the eastern dialect.

Earth Haven Farm in Ontario documents the cultural teaching which explains the cycle of life and nature of the May Grandmother Moon of Creation as follows: “The fifth moon of Creation is Flower Moon, where all plants display their Spirit sides for all the world to see. This life giving energy is one the most powerful healing medicines on Mother Earth. During this moon we are encouraged to explore our Spiritual essences”.

Lunar Perigee distance (minimum lunar distance) is 229,449 mi. (57.91 Earth radiil) on the 11th at 1:05AM EDT. Lunar Apogee (maximum lunar distance) is on May 25 at 9:39PM EST when the Moon’s distance is 251,530 mi. (63.42 Earth radii).

The waning crescent Moon appears to pass Saturn on the 13th, Neptune on the 14th, Jupiter and Mercury on the 17th, and Uranus on the 18th. The waxing crescent Moon passes Venus on the 23rd, and Mars on the 24th.

PlanetConstellationMagnitudeMoon PassagesMoon PhaseMoon Age
SunTaurus-26.811:53AM EDT, 5/19New0 Days
MercuryAries1.74.0°N, 10:00PM EDT, 5/17Waning Crescent27.42 Days
VenusGemini-4.12.0°N, 8:00AM EDT, 5/23Waxing Crescent3.84 Days
MarsCancer1.54.0°N, 2:00PM EDT, 5/24Waxing Crescent5.09 Days
JupiterPisces-1.90.8°N, 9:00PM EDT, 5/17Waning Crescent27.38 Days
SaturnAquarius1.03.0°S, 9:00AM EDT, 5/13Waning Crescent22.88Days
UranusAries5.91.71°NNW, 11:00PM EDT, 5/18Waning Crescent27.96 Days
NeptunePisces7.92.0° S, 9:00PM EDT, 5/14Waning Crescent24.38 Days


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