Jump to content


- - - - -

The Skies of May, 2021

Discuss this article in our forums

The Skies of May 2021

by Dick Cookman

May 5, 2021

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

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

Comet Journals

Comet C/2020 R4 (ATLAS) is a long period comet from the Oort Belt. It moves rapidly from Canes Venatici to Leo in May at 9th magnitude. It was at perihelion on March 1 and was closest to Earth on April 23 when it reached 8th magnitude.

C/2020 T2 (Palomar) is an 11th magnitude also from the Oort Belt. It is between Bootes, Canes Venatici, and Coma Berenices in May. It will probably remain at 10th to 11th magnitude during its closest approach to Earth on May 12 and as it passes through perihelion on July 10.

Mars Landers

The Perseverance rover utilized its MOXIE instrument to split oxygen and carbon monoxide from the carbon dioxide in the Martian air. This experiment confirmed the viability of producing oxygen for human survival on Mars and as a rocket fuel oxidizer for future Mars missions to make round trips. Perseverance also unleashed its onboard Ingenuity helicopter which successfully completed a series of 4 flights from April 19-30. Each flight was progressively longer, higher, farther, and achieved more complex maneuvers. Based on this success, NASA scientists are extending its mission and planning to utilize it as a scout for the rover.

NASA’s InSight lander has detected over 500 quakes and registered more than 10,000 dust devils since arriving on the Mars in 2018. After discontinuing attempts to drill and place its heat flow measuring equipment at a depth of 16 feet, the solar panels on the lander became coated with Martian dust, jeopardizing the mission unless winds on Elysium Planitia pick up before winters end and the rover successfully buries its seismometer cable to improve Mars quake monitoring.

After completing analysis of the drilling samples derived from the Nontron drill hole at the top of the Murray formation, Curiosity examined the 20 foot cliff called Mont Mercou at the base Sulfate Unit, then conducted further observations as it navigated along the base of the cliff in order to ascend around the outcrop to approach the top of the cliff to complete the Bardou drill hole on April 20 (Sol 3093.) The rover will now depart from the top of Mont Mercou and resume its ascent of Mt. Sharp.

Meteor Showers

Meteor showers in April include the Lyrids on the 22nd and the Pi Puppids on the 23rd. The latter is a southern hemisphere shower. The former is competing with glare from at the bright waxing gibbous Moon in Leo which, fortunately, sets before the best viewing time between 4:00 to 5:00AM.

  • May 5: Eta Aquarids. Active Apr 19 – May 28, Radiant 22h32m -01°, ZHR 60. 66km/sec. Waning Crescent Moon.: Progenitor: Comet 1/P Halley
  • May 8: Eta Lyrids. Active May 3-12, Radiant 19h08m 44°, ZHR 3, 44 km/sec. Waning Crescent Moon. Progenitor: Comet C/1983 H1 IRAS- Araki-Alcock.

Planet Plotting

May evening planets include Mercury (+1.0 to +2.9) in Taurus, Venus (-3.8) in Aries and Taurus, and Mars (+1.6 to +1.7) in Gemini. Mercury reaches greatest eastern elongation from the Sun on the 17th when it presents its best apparition of the year, setting two hours after sunset. Mars sets between 9 and 10PM EDT while Mercury and Venus are very low in the western sky after sunset and appear to make a close approach to each other in Taurus on the 29th when they are less than a degree apart. Uranus (+5.9) in Aries, Neptune (+7.9) in Aquarius; and Jupiter (-2.1 to -2.3) in Aquarius and Saturn (+0.7 to +0.6) in Capricornus are morning planets.

On the 3rd, a waning crescent Moon is 4.1° from Saturn at 4:00PM EDT. It is 4.4° from Jupiter at 9:00PM EDT on the 4th, 4.0° from Neptune at 6:00PM EDT on the 6th, and 2.2° from Uranus at 8:00PM EDT on the 10th. The waxing crescent Moon is 0.71° from Venus at 7:00PM EDT on the 12th, 2.09° from Mercury at 4:00PM EDT on the 13th, and 1.5° from Mars at 2:00AM EDT on the 16th. The waning gibbous Moon is 4.1° from Saturn at midnight on the 31st.

PlanetConstellation(s)MagnitudePlanet PassagesTimeDate
SunPisces, Aries-26.5New Moon3:00PM EDT5/11
-1.0 to +2.9
Maximum East Elongation
Venus, 0.40° NW
2:00AM EDT
Midnight EDT
VenusAries, Taurus-3.8Mercury, 0.40° SEMidnight EDT5/29
MarsGemini+1.6 to +1.7   
JupiterAquarius-2.1 to -2.3   
SaturnCapricornus+0.7 to +0.6   

May Moon

The New Moon of May on the 11th at 3:00PM EDT is the start of Lunation 1217 which ends 29.31 days later with the New Moon of June on the 10th at 6:53AM EDT. The Full Moon of May is on the 26th at 7:19AM EDT. It is commonly known as the “Corn Planting or Milk” Moon. It also is called the “Flower Moon” and will produce a Total Lunar Eclipse, the first one since January of 2019. Totality will last for 14.5 minutes, and is centered within a 3 hours, 7.5 minutes partial eclipse. The Moon will enter the Moon’s penumbra at 4:46AM when it starts to dim. At 5:46AM, the partial eclipse starts and is followed by totality starting at 7:10AM and ending at 7:28AM. Totality is followed by another partial phase which ends at 8:53AM. The eclipse favors western North America but may be visible from all of the lower 48 states and Hawaii, most of Alaska & Canada, all of Australia and Oceania, and southeast Asia. USA east coast observers may get a glance of the final stages of the partial eclipse.

Lunar apogee (maximum solar distance) is on May 11 at 6:00PM EDT. The Moon will be at 252595 miles (63.73 Earth radii), its largest distance in 2021. Lunar perigee occurs 9 hours, 28 minutes before Full Moon on the 25th at 9:46PM EDT when the Moon is at 222117 miles (56.02 Earth radii). The proximity of the Full Moon to closest approach to Earth makes it appear big and bright, the 2nd Supermoon in a row, the biggest and brightest of 2021!

In colonial times, the May Moon was the “Milk Moon” and in Medieval England, it was the “Hare Moon.” Chinese call it “Dragon Moon” and Celts named it the “Bright Or Dyan” Moon. The latter name refers to the Goddess of Animals, woodlands, and the hunt who could talk to and control the animals. Anishinaabe (Odawa and Ojibwe) people recognize it as “Zaagibagaa-giizis” (Budding Moon,) when the Sun sends the white owl to escort Winter back to the deep, cold snows of the north.

PlanetConstellationMagnitudeMoon PassagesMoon PhaseMoon Age
SunPisces-26.83:00PM EDT, 5/11New0 days
MercuryTaurus0.12.09°NNW, 4:00PM EDT, 5/13Waxing Crescent1.73 Days
VenusPisces-3.80.71°NNW, 7:00PM EDT, 5/12Waxing Crescent0.85 Days
MarsTaurus1.71.5°SSW, 2:00AM EDT, 5/16Waxing Crescent4.14 Days
JupiterAquarius-2.14.4°SE, 9:00PM EDT, 5/4Waning Crescent22.94 Days
SaturnCapricornus0.64.1°NW, 4:00PM EDT, 5/3
4.1°NW, Midnight EDT, 5/31
Waning Crescent
Waning Gibbous
21.73 Days
19.06 Days
UranusAries5.92.2°NW, 8:00PM EDT, 5/10Waxing Crescent28.81 Days
NeptuneAquarius7.94.0°NNW, 6:00PM EDT, 5/6Waning Crescent27.81 Days

  • TholianWeb likes this



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics