2019 Martian Summer Solstice

A Martian Year

A Martian Year – at One Earth Month Intervals

   Tuesday October 8th marks the summer solstice on the planet Mars as Mars transitions from spring to summer during its 684 Earth day orbit around the Sun. Seasons on Mars are marked by the planet’s heliocentric longitude coordinates using the position of Mars along its orbit around the Sun. Each seasonal start/ending point is 90 degrees apart, but because of its elliptical-shaped orbit each Martian season is of varying lengths.

   I’m not exactly sure why this particular date is used but by international agreement astronomers have selected 11 April, 1955 as 0 degrees for year 1 of this Martian calendar. What this means is that on Tuesday October 8th, Earth time, it is the start of summer during year 35 using the aforementioned calendar system.

Year 35
0 degrees — Spring Equinox — March 23 2019
90 degrees — Summer solstice — October 08 2019
180 degrees — Fall Equinox — April 08 2020
270 degrees — Winter Solstice — September 02 2020

Year 36
0 degrees — Spring Equinox — February 07 2021
90 degrees — Summer solstice — August 25 2021
180 degrees — Fall Equinox — February 24 2022
270 degrees — Winter Solstice — July 21 2022

Learn a little (or a lot) more about the exploration of Mars at the NASA Journey to Mars web site.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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July Perigee Moon and A Conjunction with Regulus

   Our Moon reaches perigee, (closest distance to Earth), for this orbit, on Friday July 5th. At that time the Moon will be at a distance of 28.51 Earth diameters, 226,011 miles (363,729 km) from the Earth.

   The 4.50-day old waxing crescent Moon is over the southwestern horizon at sunset local time and sets around midnight. About 1o east from the Moon is the ‘Heart of the Lion’, the star Regulus in Leo the Lion. The two will easily fit within the field of view of binoculars or a low power telescope eyepiece.
   Appearing lower above the western horizon are the planets Mars and Mercury.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.


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Waxing Crescent Moon on the Move

   Shortly after sunset local time on July 3rd look toward the western horizon for the 1.5-day old thin waxing crescent Moon to be close to the planets Mars and Mercury, and within about 4-5o from Pollux, one of the Gemini Twins stars.
   The following evening, July 4th, the 2.5-day old waxing crescent Moon will have moved about 15o further toward the east and will be about 3-4o from the open star cluster, M-44. Also known as the ‘Beehive Cluster’ it is a group of stars around 600 light years away and visible to the naked eye as a small ‘smudge’ of light with an apparent magnitude of around 3.70.
   Both the Moon and M-44 will easily fit within the field of view of binoculars.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


Also Follow me and other great resources at Feedspot.

July Moon at Ascending Node

   Wednesday July 3rd the 1.5-day old waxing crescent Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

   On the day of the node crossing the thin waxing crescent Moon will be close to the planets Mars and Mercury, however all three are low over the western horizon as the Sun is setting. Since this node crossing was close to the new Moon phase, about 12 hours after, there was a total solar eclipse. Visible from the Southern Hemisphere, Chile and Argentina.

   Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


Also Follow me and other great resources at Feedspot.

Mars – Mercury Conjunction

   Monday evening June 17th the ‘Red Planet’ Mars and the innermost planet Mercury will be at a fairly close conjunction, separated by only about 0.5o. The two planets will be about 5-6o from Pollux, one of the stars of the Gemini Twins. Both planets will nicely fit within the field of view of binoculars or a wide field eyepiece on a telescope.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


Also Follow me and other great resources at Feedspot.

Moon – Regulus Conjunction

   Friday June 8th the 5.60-day old waxing crescent Moon will be within about 2o from Regulus, the star marking the heart of Leo the Lion. Both will be visible high over the southern horizon at sunset local time.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


Also Follow me and other great resources at Feedspot.

June Moon at Perigee

   Our Moon reaches perigee, (closest distance to Earth), for this orbit, on Monday May 13th. At that time the Moon will be at a distance of 28.89 Earth diameters, 228,977 miles (368,504 km) from the Earth.

   The 4.68-day old waxing crescent, Moon rises is over the southwestern horizon at sunset local time and sets around midnight. About 12o east from the Moon is the ‘Heart of the Lion’, the star Regulus in Leo the Lion. Between this time and and the same time tomorrow the Moon will have passed Regulus and be a few degrees away from the star, but on the east side.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.


Also Follow me and other great resources at Feedspot.