Archive for month: April, 2021

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

Focus Constellations:  Ursa Major, Ursa Minor, Draco, Cepheus, Cassiopeia, Camelopardalis, Perseus, Auriga, Taurus, Orion, Monoceras, Gemini, Cancer, Leo, Coma Berenices, Bootes

• Comet Journals

Comet C/2020 R4 (ATLAS) is a long period comet from the Oort Belt. It moves rapidly from Aquila to Canes Venatici in April at 8th magnitude. It was at perihelion on March 1 and is closest to Earth on April 23 when it may reach 7th magnitude. It will dim rapidly in May as it appears to head toward Leo.

C/2020 T2 (Palomar) is an 11th magnitude also from the Oort Belt. It is between Bootes, Canes Venatici, and Coma Berenices in April. Closest approach to Earth occurs on May 12 when it may reach 10th magnitude, after which it reaches perihelion on July 10.

• Mars Landers

Perseverance is outfitted with equipment and instruments for numerous mind-blowing tasks on its mission. These include rock/soil caching in its 38 tubes for possible future return to Earth. To accomplish this and future astronauts returns, fuel must be provided for the return trip. To that end, the rover will utilize its MOXIE instrument to split oxygen and carbon monoxide from the carbon dioxide in the Martian air. The rover is also equipped for detailed analysis of any past and present microbiota, and its MEDA equipment will further understanding of the martian atmosphere and dust storm behavior. Perseverance will also unleash its onboard helicopter to determine flight capabilities for future missions. 

InSight has detected 2 relatively strong Marsquakes in the Cerberus Fossae region where similar quakes were recorded earlier in the mission. This quake repetition provides support for the suggestion that the region is a center of seismic activity. Each set of quakes occurred during northern hemisphere summer when winds become calmer and crustal vibrations due to winds may mask the seismic data. The lack of quake recordings between the two sets may be due to the high winds during the interval. Measurement of the quakes is also hindered by the cold winter temperatures (-148 to +32°F) at Insight’s position in the southern hemisphere. Mission scientist hope to correct this issue by using the scoop on Insight’s robotic to bury and insulate the seismic equipment tether. 

Curiosity Is now at the top of the Murray formation just below a 20 foot cliff call Mont Mercou in the overlying Sulfate Unit. The rover completed the Nontron drill hole, its last in the Murray formation, on Sol 3069 (March 25) and will now climb higher and leap forward in time to the younger Sulfate Unit.

• 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.

April 22: Lyrids. Active Apr 16-25, Radiant 13h00m -04°, ZHR 5. 30km/sec. Waxing Gibbous Moon. Progenitor: C/1861 G1 (Thatcher) 

April 23: Pi Puppids. Active Apr 15-28, Radiant 7h20m -45°, ZHR 0 to 40, 18 km/sec. Waxing Gibbous Moon. Progenitor: Comet 26P/Grigg-Skjelleru 

• Planet Plotting

In early April, Mercury (-0.4 to -2.1) in Aquarius, Capricorn, and Pisces; Neptune (+8.0) in Aquarius; and Jupiter (-3.8) and Saturn (+0.8 to +0.7) in Capricornus are morning planets. After its Superior Conjunction on April 18, Mercury (-2.1 to -1.1) enters the evening sky with Venus (-3.8) and Uranus (+5.9) in Aries; and Mars (+1.5 to +1.6) in Taurus and Gemini. From the 22nd through the 25th, Mercury, Venus, and Uranus have a series of near conjunctions. The first one is that of Venus and Uranus on the 22nd when they appear to be within less than 1/4 of a degree of one another. On the 24th, Mercury and Uranus are 3/4 of a degree apart, and Mercury and Venus are more than a degree apart on the 25th.

On the 6th, a waning crescent Moon is 3.5° from Saturn at 7:00AM EDT. It is 3.9° from Jupiter at 7:00AM EDT on the 7th, 3.9° from Neptune at 11:00AM EDT on the 9th, and 3.5° from Mercury at 6:00AM EDT on the 11th. The waxing crescent Moon is 3.6° from Venus at 9:00AM EDT on the 12th, 2.5° from Uranus at 2:00PM EDT on the 13th, and 1.9° from Mars at 1:00PM EDT on the 16th.

Planet	Constellation(s)	Magnitude	Planet Passages	Time	Date
Sun	Pisces, Aries	-26.5	New Moon	10:32PM EDT	4/11
Mercury	Aquarius, Aries	-0.4 to -1.1	Superior Conjunction	10:00 PM EDT	4/18
Mercury	Aquarius, Aries	-0.4 to -1.1	Uranus, 0.74°SE	3:00AM EDT	4/24
Mercury	Aquarius, Aries	-0.4 to -1.1	Venus, 1.16°SSE	2:00PM EDT	4/25
Venus	Pisces, Aries	-3.8	Uranus, 0.24°NNW	10:00PM EDT	4/22
Venus	Pisces, Aries	-3.8	Mercury, 1.16°NNW	2:00PM EDT	4/25
Mars	Taurus, Gemini	+1.3 to +1.6
Jupiter	Capricornus, Aquarius	-1.9 to -2.1
Saturn	Capricornus	+0.8 to +0.7
Uranus	Aries	5.9	Venus, 0.24°SSE	10:00PM EDT	4/22
Uranus	Aries	5.9	Mercury, 0.74°NW	3:00AM EDT	4/24
Uranus	Aries	5.9	Solar Conjunction	8:00PM EDT	4/30
Neptune	Aquarius	+8.0 to +7.9

• April Moon

The New Moon of April on the 11th at 10:32PM EDT is the start of Lunation 1216 which ends 29.72 days later with the New Moon of May on the 11th at 3:00PM EDT. The Full Moon of April is on the 26th at 11:32PM EDT. It is commonly known as the “Grass, Egg, Easter or Paschal” Moon. It also is called the “Pink Moon”. Unfortunately, it isn’t pink, the April Full Moon was so-named because it often occurs during the early springtime blooms of Phlox subulata—creeping phlox or moss phlox—also called “moss pink”. In colonial times, the April Moon was the “Planter’s Moon” and in Medieval England, it was the “Seed Moon.” Celts named it the “Growing or Hare” Moon and the Chinese call it “Peony Moon”. Anishinaabe (Odawa and Ojibwe) people recognize it as “Pokwaagami-giizis” (Broken Snowshoe Moon). 

The traditional Ojibwe calendar year follows a 13 moon lunar cycle. Native Americans recognize 13 moons per year because there are 13 constellations or signs of the zodiac through which the Moon moves each year. Twelve are recognized in anglo-american/european calendars and in astrology. The 13th Full Moon is found in Ophiuchus during May or June of each year. According to native folklore: “the world was created when muskrat brought mud from the bottom of the flood to be placed on turtle’s back.” The turtle’s shell is made up of thirteen central plates. These 13 scutes match the “Moons” of each year. 

At Lunar apogee (maximum solar distance), on April 12 at 2:00PM EDT, the Moon is at 252379 miles (63.68 Earth radii). Lunar perigee occurs on the 27th at 11:20AM EDT when the Moon is at 222061 miles (56.03 Earth radii). Full Moon occurs less than twelve hours earlier than its closest approach to Earth, making it appear unusually bright! This perigee is closer than it is at most perigees in 2021, making the Full Moon appear even larger and brighter.  Celestial observers may enjoy a Pink, Easter Supermoon!

Planet	Constellation	Magnitude	Moon Passages	Moon Phase	Moon Age
Sun	Pisces	-26.8	10:32PM EDT, 4/11	New	0 Days
Mercury	Pisces	-1.2	3.5°SE, 6:00AM EDT, 4/11	Waning Crescent	29.03 Days
Venus	Pisces	-3.8	3.6°SE, 9:00AM EDT, 4/12	Waxing Crescent	0.44 Days
Mars	Taurus	1.4	1.9°SE, 1:00PM EDT, 4/16	Waxing Crescent	5.60 Days
Jupiter	Capricornus	-1.9	3.9°SE, 7:00AM EDT, 4/7	Waning Crescent	25.07 Days
Saturn	Capricornus	0.8	3.6°SE, 7:00AM EDT, 4/6	Waning Crescent	24.07Days
Uranus	Aries	5.9	2.5°SE, 2:00PM EDT, 4/13	Waxing Crescent	1.06 Days
Neptune	Aquarius	8.0	3.9°SE, 11:00AM EDT, 4/9	Waning Crescent	27.23 Days