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March 2017 Skies

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March Skies

by Dick Cookman


Highlights: Comet Journal, Martian Landers, Meteor Showers,Vernal Equinox, Planet Plotting, March Moon

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

Comet Journal

The short period (5.25 years) comet, 45P/Honda-Mrkos-Pajdusakova, is in Leo in the morning sky in March. It has decreased to less than 10th magnitude. It will continue to dim as it moves through Leo and into Virgo during the Spring.

Comet 2P Enke is in early evening skies in Pisces and will move into Aquarius during March. It is approaching 6th magnitude and will be brightest near perihelion on March 10th.

Comet 41P/Tuttle-Giacobini-Kresak moves through western Leo Minor and eastern Lynx at 10th and 9th magnitude in early March, then enters Ursa Major and passes through the dipper as it approaches 6th or 7th magnitude in late March. It may achieve naked eye visibility near its perihelion on April 13th.

Comet V2 Johnson is in western Hercules at 9th magnitude. It will brighten and circle into Bootes in April and May as it approaches perihelion in June.

Mars Landers

Opportunity is headed away from Marathon Valley and Spirit Mound toward an ancient fluid carved gully about one kilometer south of its location on the inside of the rim of the 14 mile wide Endeavor Crater. The valley that the rover is to investigate cuts through the rim of the crater and is about 600 feet long. It may have been carved by water or by a debris flow composed of water and rubble. In addition to investigating the origin of the valley, Opportunity will look for differences between the rocks on the floor of the crater and the sulfate-rich rocks outside the crater. Water flows downhill into the crater and the environment deep within Endeavor may have differed in chemistry or timing from that outside.

From Sol 4623 (Jan. 24, 2017) to Sol 4643 (Feb. 14, 2017), the rover traveled 0.04 miles (0.07 km.) southwestward circuiting around Beacon Hill as it ascended the slope on the inner margin of the crater and approached its edge. The geologic formations at the edge exhibit extensive scours and grooves which may be related to the erosive action of flowing water or debris flows.

Solar array energy production averaged from 414 to 484 watt-hours. Total odometry is 27.36 miles (44.03 kilometers).

Curiosity is ascending the flank of Mt. Sharp, Gale Crater's central peak. The rover examined the Murray Formation rock layers and is approaching the Hematite Unit. The Bagnold barchan dunes superposed on the Murray Formation were studied during the first phase of the investigation of active dunes. Phase II concentrates on linear dunes found near the Hematite Unit as the rover moved southward passed some buttes and Ireson Hill, climbing higher up Mount Sharp. Since the ChemCam is "sick", extended remote sensing was conducted at Ireson Hill with the different cameras. At Stop 1 on the linear dunes, semi-parallel dune ridges with superposed sand ripples were examined and the leading and trailing slopes of the dunes were compared at Stop 2. On Sol 1620-22 (Feb. 24, 2017) a fault in the instrumentation occurred, halting further study until the problem is diagnosed and corrected.

Meteor Showers

March is characterized by very minor and infrequent meteor showers and sporadic fireballs. The Geminids on March 22nd were discovered in 1973 in Hungary when they reached a rate of 43 per hour. Confirmation occurred when they were observed again in 1975. The absence of meteor showers at this time a year is a puzzle awaiting solution by an enterprising observer. Do comets which produce meteor showers refrain from approaching the Sun from the Leo/Virgo sector of the Solar System? If so, why? Let the rampant speculation began.

Vernal Equinox

The Spring Equinox is at 6:29AM on March 20th under the light of a waning crescent Moon.

Planet Plotting

March morning planets include Saturn (+0.5 to +0.4), and Jupiter (-2.3 to -2.2). Saturn rises well before the Sun in Sagittarius and is in the southeastern sky before sunrise. Jupiter (-2.3 to -2.2), in Virgo, rises before midnight and sets after sunrise. It is gradually getting brighter as it approaches opposition in April. Neptune (+7.9) is in conjunction with the Sun on the 1st and at mid-month will appear in Aquarius.

Mercury (-1.1 to -0.8), Venus (-4.6 to -4.7) and Mars (+1.1 to +1.3) are the brightest evening planets. Mercury does not appear in the sky in Pisces until the last half of the month. It will be separated from Venus by 8.5° in Pisces on the 18th and by 2.1° from Uranus on the 26th. Venus in Pisces will disappear in the glow of sunset before its inferior conjunction with the Sun on the 25th. Mars (+1.3 to +1.5) is in Aries.

PlanetConstellationMagnitudePlanet Passages
SunAquarius, Pisces-26.8New Moon, 3/27 10:57AM EDT
MercuryPisces-1.1Neptune, 1.0°NNW, 3/4, 7AM EST
MercuryPisces-1.2Superior Conjunction 3/6, 7PM EST
MercuryPisces-1.1Venus, 8.5°NNW, 3/18, 2PM EDT
MercuryPisces-1.1Uranus, 2.1°SSE, 3/26, 6AM EDT
VenusPisces-4.2Mercury, 8.5°SSE, 3/18, 2PM EDT
VenusPisces-4.2Inferior Conjunction 3/25, 6AM EDT
MarsAries+1.3 to +1.5 
JupiterVirgo-2.3 to -2.2 
SaturnSagittarius+0.5 to +0.4 
UranusPisces+5.9Mercury, 2.1°NNW, 3/26, 6AM EDT
NeptuneAquarius+7.9Solar Conjunction 3/1, 10PM EST
NeptuneAquarius+7.9Mercury, 1.0°SSE, 3/4, 7AM EST

March Moon

The New Moon of March 27th at 10:57AM EDT is the beginning of Lunation 1166 which ends 29.04 days later with the New Moon of April 26th at 8:16AM EDT.

The Full Moon of March in Leo occurs at 10:54AM EDT on the 12th. The March Moon is called the “Sap, Crow, or Lenten Moon”. Colonial Americans named it the “Fish Moon”. To the Celts it was the “Moon of Winds”, and the Chinese refer to it as the “Sleepy Moon”. Medieval English thought of it as the “Chaste Moon”, and the Anishinaabe (Odawa and Ojibwe) people of northern Michigan recognize it as "Onaabani-giizis" (Snowcrust Moon).

Lunar perigee (closest to Earth) is 229,302 miles or 57.86 Earth radii on the 3rd at 2:29AM EST. Apogee position in orbit (maximum orbital distance) is at 251,415 miles (63.44 Earth radii) from Earth on the 18th at 1:00PM EDT.

Cecil Adams’ reasons why we need the Moon:

Reason #4: "It's a steadying influence. In order for life to develop on earth, we needed stable temperatures and a regular climate. Variations of even one degree in earth’s axial tilt relative to orbit may have led to ice ages in the past. The moon, with its large mass, acts as a major stabilizing force on our axis (as well as helping keep us within the habitable zone). Without it, we could have ended up like Mars, whose moons are much smaller and whose tilt may vary over a span of 60 degrees. In the search for extraterrestrial life scientists regularly prioritize planets with similar-sized moons attached.

With no moon, of course, our fates would be drastically different because of the misalignment of our astrological signs, but on the plus side we wouldn’t hear any more about that lunar-cycle/menstruation myth. Would mooning still be popular? Would Pink Floyd still exist? These are questions that have not been subjected to the hard discipline of the sciences, leaving us to only imagine the potential horrors in store. Missed opportunities for night vision notwithstanding, let’s be grateful for what we have.”

Explanation: The Earth and Moon are gravitationally linked and behave as a system. In the Earth/Moon system, both bodies revolve around a common barycenter located about 1000 miles below the Earth's surface between the Earth's center and the center of the Moon. As the Moon orbits the barycenter each month, the Earth has a monthly wobble as its center completes a 18,850 mile circuit around the same barycenter.

Angular momentum associated with daily rotation stabilizes our axis. The tilt cycles between 21.5° to 24.5° over 40,000 years. Angular momentum also deforms Earth's shape to an oblate spheroid (pumpkin). Tidal effects of the Moon (and to a lesser degree the Sun) are slowly realigning the long dimension of the spheroid so that it parallels a line connecting the centers of each body. The war between this tidal effect and Earth's angular momentum gradually reduces Earth's rotation rate which in turn is tied to the monthly orbital period of the Moon as the angular momentum lost by Earth is transferred to the Moon causing it to speed up and slightly increase its period and distance from the barycenter.

PlanetConstellationMagnitudeMoon PassageMoon Phase/Age
SunAquarius-26.810:58PM EDT, 3/27New ~ 0 days
MercuryAquarius-1.16.3°SSE, 7AM EST, 3/29Waxing Crescent ~1.33 days
VenusPisces-4.210.7°SSE, 3:00PM EDT, 3/27Waning Crescent ~28.71 days
MarsPisces+1.34.1°SSE, 2:00PM EST, 2/1Waxing Crescent ~2.96 days
MarsPisces+1.55.3°SSE, Noon EDT, 3/30Waxing Crescent ~2.54 days
JupiterVirgo-2.22.3°NNE, 6:00PM EDT, 3/14Waning Gibbous ~18.70 days
SaturnSagittarius+0.43.4°N, 7AM EDT, 3/20Waning Gibbous ~ 21.38 days
UranusPisces+5.93.4°SSE, 1PM EST, 3/1Waxing Crescent ~2.63 days
UranusPisces+5.83.4°SSE, 1AM EST, 3/29Waxing Crescent ~1.08 days
NeptuneAquarius+7.90.11°WSW, 4AM EDT, 3/26Waning Crescent ~27.25 days


Hi Dick.  I always like to read your "journal" entries.  I often use them for inspiration when planning observing sessions.  Like Franklin's Poor Richard's Almanack, only for astronomy and serialized.  Thank you for your dedication and contribution.


- Jim

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