April Moon at Descending Node

2jan-descending-node   Friday April 21st the 24-day old waning crescent Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
   
   On the day of the node crossing the 24-day old waning crescent Moon will be over the southeast horizon at sunrise local time. The graphic includes the ecliptic and other planets so you can see the relationship between planets, the Moon, and the ecliptic. At times like this, with several planets arranged across the sky it is easy to visualize the ecliptic.   
   
   

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.

Mercury at Inferior Conjunction

orbital-positions   Thursday April 20th the innermost planet Mercury reaches inferior conjunction. At inferior conjunction Mercury will move between the Earth and the Sun – much like the position of the Moon at new phase. The graphic to the right shows the planet positions relative to the Earth and Sun for both inner planets and outer planets.

mercury at inferior conjunction   While at this inferior conjunction Mercury will not be directly in line with the Earth and the Sun – on the ecliptic. Mercury has an orbital inclination of 7o with respect to the ecliptic. So like our Moon, Mercury during each complete orbit, will cross the plane of the ecliptic moving north (ascending node) and also moving south (descending node). In this situation Mercury is north of the ecliptic and 6 days away from its descending node on April 26th.

   
   
   

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.

Sun Not in Taurus

April 19th  According to the pseudoscience of astrology the Sun enters the constellation of Taurus the Bull on Wednday April 19th. When in fact the actual position of the Sun on the 19th is still within the boundary of the constellation of Aries the Ram, as this graphic shows. Actually the Sun had just entered Aries the day before on April 18th.

   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
   
   
   
   
   
   

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.

Sun Enters Aries

April 19th   Tuesday April 18th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Pisces the Fishes and into the constellation of Aries the Ram. 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.
   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
   
   
   


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.

April Moon at Ascending Node

   Friday April 7th 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 April 7th the 11-day old waxing gibbous Moon will rise with the constellation Leo the Lion and is located near the Lion’s tail, the star Denebola.

   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 Moon at Descending Node

2jan-descending-node
   Saturday March 25th the -day old waning crescent Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
   
   On the day of the node crossing the thin 26.7-day old waning crescent Moon will be over the southeast horizon at sunrise local time.

   
   
   

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.

Venus at Inferior Conjunction

   Saturday March 25th the inner planet Venus reaches its orbital position known as inferior conjunction.
   This is one of four points along an inner planet orbit. At inferior conjunction Venus is between the Earth and the Sun – sort of like our new Moon phase – but not necessarily directly in line. If that were so, inferior conjunction at the same time as Venus in direct line with the Earth and Sun (a node crossing at inferior conjunction) it would be a somewhat rare transit of the Sun by Venus. These happen as a pair of transits about one time each century with the last pair of Venus transits in June 2004 and June 2012. Here are some pictures of the June 2012 Venus Transit. Here is a link to the Vimeo web site to watch a video of the 2012 Venus Transit.
   By the way the next pair of Venus Transits are December 2117, and December 2125.

    At this inferior conjunction Venus is north of the ecliptic heading south toward its descending node and ecliptic crossing next 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.