Waning Gibbous Moon Near Spica


   Sunday evening April 1st the waning gibbous Moon will be within about 6o from the blue-white star Spica in 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.

A Second Blue Moon

   Saturday evening March 31st the second full Moon of this month will be rising in the east at sunset local time. According to the popular definition for a ‘Blue Moon’ the second full Moon in a month is known as the ‘Blue Moon’. This happens about every 2.5 years with this year being a little more different in that there were two Blue Moons, the first this past January and the second Blue Moon this month.

   
   
   

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.

Saturn at Western Quadrature

saturn-west-quadrature   Thursay March 29th, the position of the planet Saturn with respect to the Earth and the Sun places this ringed planet at what is called western quadrature. Saturn is at a 90 degree angle from us as this graphic shows. Think third quarter Moon as that is a fair comparison of the relative positions. At this position Saturn leads the Sun across the sky from east to west as the Earth is rotating, meaning that Saturn rises before the Sun and also sets before the Sun.

Saturn currently is within the constellation of Sagittarius the Archer as this graphic shows. From the northern hemisphere, looking toward the southern horizon, you can find Saturn to the east, left, from the reddish star Antares. Between Saturn and Antares is Mars, about 2-3o from Saturn. To the right from Antares is the planet Jupiter.

Learn a little (or a lot) about Saturn by visiting the Cassini at Saturn mission web site.
Click here to go to the Cassini Mission web site.

   This is a short 5 minute video I made as part of a live musical performance called “Orbit”. This is a piece from the much longer tour of the solar system performance and video and shows Saturn and some of its moons as viewed from the Cassini spacecraft that month.

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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 Moon at Ascending Node

   Tuesday March 27th the waxing gibbous 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 Tuesday evening March 27th the 10.5-day old waxing gibbous Moon will be within the boundaries of Leo the Lion and about 7o west (right) from the ‘Heart’ of the Lion, the star Regulus.

   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.

March Perigee Moon

   The Moon reaches perigee, (minimum distance from Earth), this month on Monday March 26th. At that time the Moon will more or less be at a distance of 28.90 Earth diameters (369,106 km or 229352 miles) from the Earth.
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*

On the day of perigee the 9.5-day old waxing gibbous Moon rises at mid-afternoon and is located between Procyon in Canis Minor and Regulus in Leo the Lion.

*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.

Mars at Western Quadrature

orbital-positions   Saturday March 24th the position of the planet Mars, with respect to the Earth and the Sun, places this planet at what is called western quadrature. At that orbital position Mars, and actually any outer planet at their respective quadrature, is at a 90 degree angle from the Earth as this graphic shows, and the banner graphic at the top of the page shows. Think last quarter Moon as that is a fair comparison of the relative positions of Earth, Sun, and Mars. At this position Mars leads the Sun across the sky from east to west as the Earth is rotating, meaning that Mars rises before the Sun.

   Saturday morning finds Mars and two other visible planets, Saturn and Jupiter, spread across the morning skies from southeast to south.

   
   
   

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.

Moon Traverses Taurus


   Wednesday and Thursday evenings March 21st and 22nd the waxing crescent Moon will pass across the constellation of Taurus the Bull. It will first be several degrees from the open star cluster the Pleiades and then the next day the Moon will be within 1-2o from the reddish star Aldebaran and the open star cluster the Hyades. The latter should prove to be a striking sight through 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.

2018 March Equinox

   Tuesday 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 elongated 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!

  Northern hemisphere spring officially (well at least astronomically) begins at 16:15 UT on the 20th (11:29 am CDT) 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.

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


   Celebrate Solar Week March 19th-23rd. Click here to go to the Solar Week web site.

   
   
   
   During a trip to Quito Ecuador to visit one of the exchange student we had hosted, and her family, we spent the day at a Museum on the equator, Mitad del Mundo. I brought along my over-sized protractor knowing in advance that we would be at the museum. So at mid-day I had my wife stand on the equator (yellow line) and hold a string to the top of her head while Cathy, a sister of our exchange student, held the protractor. This was done during the summer so the Sun was over the northern horizon at mid-day and the Sun’s angle above the northern horizon was around 75o.

   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).

   
   
   


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.

Like Ships Passing in the Night

   Over the next week or so the two inner planets will pass by each other coming the closest on the 19th when the two will be less then 4o from each other. With only casual observation one should notice that both planets are moving with respect to each other, but in opposite directions. Mercury is recently past its eastern elongation and is now moving westward, in retrograde, toward the Sun and inferior conjunction. On the other hand, or orbit, Venus is moving eastward out from a recent superior conjunction, opposite side of the Sun, toward its own respective eastern elongation.

   
   
   
   This animated graphic shows Venus and Mercury over a period of several days from March 16th to the 29th of March. The time is set for 7:15 pm CDT and in the first several frames the planets are first shown as they would appear at 7:15 pm, then I added labels, then their respective orbits. To make the animation easier to see I also turned off daylight, and then finally the labels were turned off then back on at the end.
   
   
   
   

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.

Waxing Crescent Moon in Conjunction with Mercury and Venus


   Sunday evening March 19th the thin 1.5-day young waxing crescent Moon, and the two inner planets, Venus and Mercury, will be over the western horizon about 1 hour after sunset local time. All three will fit within the width of a 7×50 binoculars field of view (about 7o).

   
   
   

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.