Mars and Jupiter at Heliocentric Opposition

31oct-view-from-mars   Thursday December 22nd the planets Mars and Jupiter are aligned in an arrangement known as heliocentric opposition. The two planets are on opposite sides of the Sun and are approximately 180o apart in heliocentric longitude as measured around the celestial equator. Mars has a heliocentric longitude of approximately 10o, while Jupiter is at 190o. However the two planets are not necessarily at the same level (above or below) relative to the ecliptic. Both planets are south of the celestial equator with Mars at 12o South Declination in Aquarius the Water Bearer, and Jupiter, at 6o South Declination, is in the constellation of Virgo the Harvest Maiden.

   
   
   

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.

March 2015 Equinox and Solar Eclipse

   Friday March 20th is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’ (starts). For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At mid-day on the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

seasons-ani  Northern hemisphere spring officially (well at least astronomically) begins at 22:45 UT (4:45 pm CST) on the 20th when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. At this location the Sun is within the constellation of Pisces the Fishes and not just entering Aries the Ram as the pseudoscience of astrology would have you believe.

    To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   The time of this equinox is about 13 hours after a new Moon phase and a solar eclipse. This picture shows the shadow of the Moon cast on the Earth during a solar eclipse as seen from the International Space Station.

   Click here to see the online world sunlight map used to make the day/night graphic at the top of the page.

sun-earth   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

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[centup]
Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Sun Enters Aquarius

feb-view from earth   Monday 16 February at 20 UT (2 pm CST), the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Capricornus the Sea Goat and into the constellation of Aquarius the Water Bearer. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position. Which will be Wednesday 18 February when the sun is not in Pisces according to astrology.

   
   
   
[centup]
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Mars and Jupiter at Odds – Heliocentric That Is

31oct-view-from-mars   Friday October 31st the planets Mars and Jupiter are aligned in an arrangement known as heliocentric opposition. The two planets are on opposite sides of the Sun and are approximately 180o apart in heliocentric longitude as measured around the celestial equator. Mars has a heliocentric longitude of approximately 310o, while Jupiter is at 130o. However the two planets are not necessarily at the same level (above or below) relative to the ecliptic. Mars, at 24.53o South Declination, is only a few days (26 October) past its maximum declination of 25o south of the celestial equator in Sagittarius. Jupiter, at 15o North declination in the constellation Leo the Lion is north of Mars by nearly 40o.

   
   
   
[centup]
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

March 2014 Equinox

   Tomorrow, 20 March, is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’. For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

seasons-ani  Northern hemisphere spring officially (well at least astronomically) begins at 11:57 am CDT (16:57 UT) Thursday 20 March when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   Click here to see the online world sunlight map used to make the day/night graphic above.

sun-earth
   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

This slideshow requires JavaScript.


   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

September Equinox

Click on graphic to see it full size.

Click on graphic to see it full size.

   On Sunday 22 September at 3:44 pm CDT the Sun will have reached the astronomical coordinates of 0 degrees declination and 12 hours of right ascension, or RA. This places the Sun within the boundaries of the constellation Virgo the Maiden, or as some would say, “the Sun is in Virgo.”
Click on graphic to see it full size.

Click on graphic to see it full size.

   Declination is the astronomical equivalent to latitude measuring from 0 degrees at the equator to 90 degrees at either pole. Right ascension, or RA, is like longitude except that there is only east RA. The globe is divided into 24 sections, and like meridians of longitude, these hour circles are 15 degrees wide at the celestial equator and taper to a ‘point’ at the north and south pole respectively. In RA the ‘hour’ circles are counted from 0 hours to 23 hours. The 0 hour circle is at the intersection of the ecliptic and the celestial equator in the constellation of Pisces the Fishes.
Click on picture to see it full size.

Click on picture to see it full size.

   In a class lesson about seasons today would be one of the two days during the year when the Sun would be described as being over the Earth’s equator. If you were at the Earth’s equator the Sun would have an altitude of 90 degrees, or straight up in your sky at your local time for midday. At that moment there would not be a shadow. However at any other latitude, north or south at midday, the Sun would be at an angle less than 90 degrees and there would be a midday shadow. (Midday is the local time when the Sun is halfway between local rising time and local setting time. At any midday the Sun is at its maximum altitude above the southern horizon in the northern hemisphere, or is at its maximum altitude above the northern horizon in the southern hemisphere.)
   What is often most notable about an equinox day is the reminder that equinox means equal night as a reference to there being equal amounts of daylight, and night. Also on an equinox day the Sun would rise due east and set due west for virtually everywhere on the globe. The times for sunrise and sunset would be approximately 12 hours apart, and the rising time would be around 6 am local time, and the setting time would be around 6 pm local time.

Hola Moon doh

Hola ‘Moo’ndo! Think Globally.

   So why “September Equinox” instead of using the more familiar “Fall Equinox”. Primarily because the southern hemisphere is also changing seasons on this day however for the southern hemisphere this is the start of their spring season. Despite the opposite seasons it is somewhat of a northern hemisphere bias that traditionally we would call this day the “Autumnal or Fall Spring Equinox”, and in March we would say the “Spring” or “Vernal Equinox”. I favor the use of the name of the month so that regardless of which hemisphere it is just simply the March equinox or the September equinox, and by extension we would also have the June solstice and the December solstice..
   
   This short video shows students at Colegio Menor San Francisco de Quito, a school in Quito Ecuador, measuring the altitude of the sun hourly on the day of the 2004 September Equinox. They were taking part in Project SunShIP, Sun Shadow Investigation Project. There are also some pictures showing a local midday shadow from other participating schools in the United states.

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.